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2000 M5 Auction Buy Mistake - A Build Thread

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15K views 159 replies 29 participants last post by  nyc951  
#1 ·
Hey everyone, I've had an account here for a while but never posted much. I've always enjoyed making these threads to share ideas and learn from each other so figured I'd start one here.

In late 2023 I bought a nicely optioned but somewhat high mileage 2000 M5 in silverstone over black extended leather on one of the popular auction sites, and surprise surprise, it is a complete piece of ****. "Well sorted" my behind...but anyways I get what I deserve buying an old BMW site unseen. So follow along as I spend more money than I paid for the car just to make it decent again.

The overall goal for this car is to be a sort of daily driver for the next couple years before getting an EV to take over that role once the tech matures a bit more and I have a decent option that isn't a Tesla, then the M5 can be a garage queen next to my 1994 NSX. I go into the office 2 days a week so don't drive all that much to begin with.

I had been driving a 2003 540i/6 daily since 2018 and put more than 60,000 miles on it, and I recently sold it in late 2024 and have been daily driving the NSX since then due to all the issues this car has. I daily drove this car for about 6 months in early 2024 after overhauling the suspension as a sort of shake down to see what problems would pop up with the drivetrain and how much oil it would burn (roughly a quart every 1500 miles, not too bad) and it has been mostly parked since then when most of the dash lights came on and the diff started leaking pretty badly.

Where I'm at currently is part way through a full restoration/rebuild of the drivetrain with the engine stripped down to the bare block, but here's some pics of what has happened up to this point.

Day of delivery. Pretty sure the truck driver scraped up the bottom of the front bumper during the unloading process but I didn't get outside in time to see it happen. Cosmetically the car is quite good, mechanically, not so much.

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Interior

The extended leather interior is in decent shape except for one splitting seem on the driver seat. The 4:3 nav system absolutely needs to go though, I'm not sure what to replace it with...maybe just a 16:9 nav and Bluebus which is what the 540 had. The Android units, even the pricey ones, just seem sort of glitchy and problematic.

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One of the first things I did was swap the nearly perfect birch anthracite trim over from the 540, it's always been my favorite E39 trim. Also installed the reupholstered facelift steering wheel and recall-replaced airbag from the 540.

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Not pictured, but I grabbed an LCM4 and RLS sensor from a junk yard E53 X5, automatic light switch from eBay, and brand new cluster trim piece from FCP. The existing RS sensor was busted so I removed it and installed a new "RLS" prism using this kit http://automotivedesigngroup.com/catalog/i100.html, coded the LCM4 to the car, installed the new sensor, and enabled automatic lights. After some trial and error, this is the process if anyone else has to do it.

1) Install the used LCM in the car.
2) Code the VIN and odometer to match with PASoft.
3) Code the module to the car with NCSExpert.
4) Using NCSExpert or Dummy, set "AUTOM_FAHRL_STEUERG" to "aktiv". PASoft does not seem to expose this option.
5) Code whatever other options you want.

I originally bought the little 3D printed relocation piece for the TPMS button, but it was really ugly so I made my own solution by cutting up both the original button and the blanking plate and gluing them together for a completely OEM look.

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The cluster pixels were going out of course, so I replaced the display and ribbon cable. I had swapped an M5 cluster into the 540 years ago and went through this process once already so had the original 540 cluster as a spare for parts, which came in handy when the white display housing crumbled when I took it apart. Some people don't like it but I use the drill method to get to the screws to bypass the risk of removing the cluster needles. Display back to 100% working.

I originally wasn't a fan of the black cluster face and was considering swapping the grey one from my 540, but it grew one me and I kept the black.

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I've never cared for the light up shift knob or integrated boot, so new leather boot and ZHP knob.

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The driver door control panel was missing most of the paint on the switches so I got a junk yard one to swap the switches over only to find that it was a completely different design. Apparently BMW redesigned these switches between MY2000 and MY2001, so I found a newer panel with the mirror button on Ebay and swapped it out. The buttons on the new version have a nicer tactile feedback than the old design which feels kind of mushy.

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Suspension

The M5 was lowered on blown out Koni shocks and Dinan springs and felt like it was about to flip over if you hit a decently sized bump at highway speeds and generally just rode terribly. So I ordered new OEM everything except for some control arms which had already been replaced and were still ok. (The Dinan springs were probably fine, but I don't care to lower this car so I gave them away on FB market)

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Rear suspension done and everything cleaned, also replaced the fender liners.

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The car originally came with Moosehead monoballs, so I replaced them with the GAS sealed units instead. I know Moosehead is quality stuff but I don't care for the unsealed bearing. Taking them apart, they look perfect internally so if anybody wants a set of Moosehead bushings DM me.

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The center link and tie rods had been replaced at some point but weren't in great shape so I ended up replacing those too. After an alignment everything checked out good except for the driver side front castor which read 5.8*, to the 6.1* on the passenger side. The driver side strut tower is mushroomed a bit and the car pulls ever so slightly so taking that shock off and using an air hammer to beat the strut tower back into shape is on the to do list still, along with swapping in E38 strut mounts which are steel instead of aluminum and should provide motor support to the strut tower to prevent mushrooming.
 
#152 ·
If you're doing audio upgrades, can I convince you to jump down the aftermarket DSP rabbit hole?! I run stock speakers (well, I added aftermarket 8" subs) with an Audison AP 8.9 DSP and spent a bunch on time tuning it with REW (Room EQ Wizard). I am absolutely convinced an aftermarket DSP yields better return than the fanciest speakers.


JBL used to have a nice one with auto-QE tuning. It looks like they have a newish model, but I don't know if it does auto-EQ.
 
#153 · (Edited)
How did you do that? Did you keep the factory DSP? Or rip it all out? I would like to go fully aftermarket, but the fact that the factory DSP system contains the crossovers for the 6 tweeters, 4 midrange speakers, and 2 deck lid subs sort of scared me off of removing it. In a perfect world I would rip out all the radio crap in the trunk and replace it with a standard head unit/amplifier/speaker setup, but with all the different speakers covering different frequency ranges that sounds very tricky to get right.
 
#154 · (Edited)
Short answer: I removed the factory DSP and rewired lots of things.

Longer answer: At the time I wanted the option to go back to stock so I made a custom PCB to adapt from the OEM connectors without having to hack the OEM harness. In hindsight I'm never planning to go back to OEM now, so this was overkill. I'll take a picture tomorrow when there some ambient light to work with.
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The really cool part about the AP 8.9 DSP I have is that it is an amplifier that will also do crossover filtering and much more -- check various youtube videos on the amount of flexibility it offers prima 8.9 tuning - YouTube

The learning curve is steep, but if you're willing to go down this path the results can be excellent. I'm so happy with it and I do something similar for all my various home speakers as well now. Below is the before (red) and after (blue) of my tuning -- both using the stock speakers, just with different DSP settings.

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Edit: On quick glance, I'm seeing references to Audison having an auto-tune capability, of which I'm guessing came out with the newer models (it definitely didn't exist when I installed mine). That would at least make things easier when it comes to tuning!
 
#155 ·
Love this update...

also I mean, who else makes speakers with KEVLAR these days anyways? I was fully amazed by the elaborate use of kevlar when I replaced my suspension and got all up in the rear parcel shelf speaker boxes... it's actually more like artwork IMO! So not totally surprised at your claim here that with a better DSP you can get better sound out of the stock speakers rather than replacing them. Which I understand is completely atypical of a normal car stereo situation.
 
#156 ·
Follwing up -- photos of my setup.

OEM Navigation DVD reader was removed. I found a non-M5 trim cover at a junk yard and swapped that in.
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My philosophy was to enable reverting back to OEM so I tried to avoid chopping anything up behind the cover.
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And info on my subwoofer setup: 01 E39 M5 - Subwoofer Replacements | BMW M5 Forum and M6 Forums
 
#157 ·
I love it, I'm tempted to build a PCB like that now. Haven't had to do a layout since college though hah.

How did you handle the tweeter channels? With 8 output channels and 10 speakers did you share a channel for front and rear tweeters? The Bavsound speakers are just a woofer/tweeter combo so I wonder if I could just ditch the 3rd speaker up front.

Before I take anything apart I'm thinking I'll feed white noise into the system from 20hz-20khz and scope the spectrum delivered to each speaker to get an idea of how the stock DSP system handles crossovers for each speaker which would be a good starting point for tuning a proper DSP with a microphone.

And how is the audio output quality with the Avant 4? Opinions seem mixed to slightly positive, not that I'm an audiophile by any means.
 
#158 ·
I omitted two of the channels. From the schematic, it looks like the front mids -- those 3" (?) ones as I figured there was already the 5.25" (I can't remember any of the sizes).

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If you did a PCB layout, what software would you use? I can certainly share my native Kicad files. Or I can at least figure out how to update the schematic so the pinout show correctly. I'm also pretty sure I had to order a bunch of these to meet minimum order requirements and have an unpopulated board laying around. If you're interested, just let me know and I'll look for it.

The audio output quality I can't really say as I've tuned everything to my satisfaction with the aftermarket DSP. I do recall there being a ground noise on the subwoofers, but that was due to something with the DS18 mini-amp's power scheme. You'll note that I jumped power on the DS18 directly to where the DSP is getting power... That was not my original intent.

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Otherwise I am incredibly happy with my Avin! All the niceties of a modern head unit (especially Carplay), the best looking design (in my opinion), and only minimal bugginess. I generally only use Carplay, I-Bus App, sometimes the radio, and don't consider myself a power user; so more bugginess might occur if you start loading even more apps. Case in point, I did have Sygic GPS Navigation at one point and it made everything really buggy.

I can't ascertain whether it helps or not, but I also did an overkill mod and installed aftermarket heatsinks & fans as I read that it will throttle itself if too hot. I can't seem to track down most of the receipts but it went something like:


I'm pretty sure Avin has an upgraded processor now (akin to a Avant4.1 but never officially renamed) -- I bought one in the first batch of shipments and everything is still running very well.
 
#159 · (Edited)
Man that is such a clean setup. For the audio I'm planning on doing it in stages, probably speakers first, then Avin system, then as a stretch goal bypassing all of the junk back there sort of like you now that you've brought it to my attention. For PCB design I've used Eagle most recently but most of them are pretty similar IIRC. The appearance was the main reason I went with the Avin over the other models, I know they're all basically the same inside but it seems to be the closest to stock looking, I went with the lowest tier processor because I don't plan on really using anything but carplay. That's a good tip on the fans for the unit it gets really hot here.

I got the car back today and I'm quite happy with the outcome. The exhaust sound is about perfect for a cruiser, you can hear it when you get on it but absolutely zero drone. I'll have to get some videos of that soon. It's amazing how you can just ditch the mufflers entirely and barely make the car louder and it's a shame theres no way to reclaim some trunk space. So far I haven't noticed any additional noise from the solid diff mount but I have also been driving with the windows down since I haven't recharged the AC yet.

In this pic you can see he added some pretty large gussets to the mounting brackets on the Turner pipes to make sure they don't crack off.

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We opted to leave off the transmission to exhaust bracket, since with the flex pipes it shouldn't really be needed and BMW pretty much perfectly balanced the exhaust over the center support so it doesn't put any force up or down on the headers. I might add it back later for good measure though. Everything is TIG welded.

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So far no leaks that I can find and fingers crossed it stays that way for a while. Next thing is charging the AC back up and putting those rear braces back on in the rear, and doing a bit of cleanup on the wiring and hooking up the electric cooling fan. It's mostly wired up I just have to make an adapter harness to plug it into the SAP wiring.

There is a very distinctive smell in the engine bay that I've only ever come across on the engines I've rebuilt with ceramic coated headers, it's nothing you'd normally smell on an engine so the coating is the only thing I can think of. Tempted to have the under carriage dry ice blasted but there's probably no point.

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There was some ticky lifters at first but after driving the car 40-50 miles it's sounding very nice and smooth at idle. I'll probably give it another 100-150 miles this weekend then drain the 15w40 conventional tractor oil and switch to 10w60.


This has ended up being one of the biggest car projects I've ever done, to the point that I've probably done more work on this car than my NSX which I've been working on for almost 10 years. To recap...

Driveline
  • Diff seals
  • Diff bushings w/solid aluminum front bushing
  • Rebuilt axles
  • New driveshaft CV
  • New wheel bearings all around
  • Center support bearing and guibo
  • Engine, transmission, and exhaust mounts
  • Rebuilt shifter linkage + E60 545i shift lever + ZHP knob
Chassis/Suspension/Steering
  • Rear shock mounts replaced + custom 1/4" spacers for reinforcement and ride height adjustment
  • E38 steel front shock mounts, reinforcement plates, strut towers hammered back to shape
  • New OEM shock/strut assemblies and all rubber parts
  • Monoball thrust arm bushings
  • Lemforder center link and tie rods
  • Rear subframe bushings
  • Spoon rigid collars for front and rear subframes
  • New PS hoses
Brakes
  • Rebuilt + powder coated brake calipers
  • Akebono pads + turned rotors
  • New brake sensors and hoses
  • ABS module repaired
  • Custom mid pipe hard lines
Body
  • Rear diffuser wrapped satin black
  • New front and rear fender liners
  • Installed missing pork chop
  • Custom facelift headlights, facelift tail lights, OEM LED license plate lights
Engine
  • Engine rebuilt (but reused piston rings)
  • All rubber hoses/seals/sensors/etc. replaced
  • WPC treated pistons, wrist pins, main bearings, and rod bearings
  • Rebuilt VANOS assemblies with later year parts and oil screens removed
  • Repaired oil pan w/ball valve
  • Muffler deletes
  • Exhaust separated with V band clamps at collectors and axles for ease of service.
  • Supersprint headers
Interior
  • Leather conditioned
  • Driver seat back repaired + swapped to passenger side
  • New driver seat bottom foam
  • Seat rail trims removed
  • All doors resealed
  • New lock actuators + double lock permanently disabled
  • Custom titanium lock pins because why not
  • Birch anthracite trim
  • Bavsound speakers (WIP)
  • Avin Avant 4 head unit + backup camera (WIP)
  • Facelift ///M steering wheel
  • Repaired dash pixels
  • LCM4 retrofit with LEDs everywhere
  • Auto lights retrofit
  • TPMS button relocated to cluster surround
  • Euro center armrest
  • Front/rear dash cam
  • Homelink garage door opener and microphone holes in the ceiling deleted
  • Lots of broken plastic bits repaired or replaced
I am somewhere in the neighborhood of $25k in parts alone. Probably closer to $30k. And I still need a headliner...