Without question, this hits the nail on the head squarely. Having started tracking/racing 40 years ago, I did for a short time about 15 years ago entertain the idea of having fun with the M5 on the track as many, many of us forum members did at the time. First time out I thought I was prepared enough for driving the car 10/10ths at VIR full course -- Dunlop SSR r-comp tires, Hawk HT10 race pads, brake ducts opened, Dinan springs, bars, shocks, Ground Control camber plates at -2.5 front. I ended up melting a brake caliper piston seal -- fun times.I tracked the M5 once. Once was enough, while I have the M3's-- they're just dramatically, significantly, not at all close, better cars to track. On "normal" (not ring) tracks they're faster, but that's not what I mean-- I mean they behave better at the limit, don't go through consumables as fast, and feel generally... at home. The M5 does not-- you're always fighting with/managing the mass.
So...on went one of the very best mods I did on the E39 M5 -- Stoptech BBK. With PFC01 race pads, it was incredible how amazing the transformation was from stock calipers with race pads. I used Ti shims in the BBK also for boot and seal protection. Braking issues were solved.
In the end, it just wasn't fun. The car suffers from too much mass and from the traditional Salisbury LSD which provides enough locking on deceleration to make the car push on turn-in of slower corners and not enough locking on acceleration from the apex out, etc, etc.
However, this is way, way off topic from the OP's original question. I'll just insert below my comment from my BaT auction about differences in 2001-2003 M5s with the added note that it was March 2000 production where the piston ring update was applied to the S62 during the 2000 model year run:
Here’s what I know about year differences. First off, during the 2001 model year as of November 2000, they switched to an electric VANOS accumulator on the S62 (same on Z8) which was then unchanged through 2003 end of production. Early 2001 models had the wiring and programming to accept it, so many (most all?) were retrofitted under warranty. This car always had the later accumulator as it was built in July 2001.
For 08/2001 production onward, there was an update to the VANOS spring plate thickness and lock ring. I believe they did this to assuage concerns about rattle, but I’ve not ever heard of this being an issue on 2001 models. The M5board hasn’t shown evidence of any VANOS issue related to this change all these years.
Also in 2002 they added an automatic position to the headlight switch so that they will come on/off depending on ambient light levels.
The 2002 model year is a bit of an oddity in one key area — airbags. BMWNA had a one-year-freak-out over airbag liability concerns, and they made the rear airbags optional forcing buyers to order the car with them specifically. Hence you’ll find almost all 2002 models in North America do not have rear airbags. In 2003 they went back to like it was for 2001 — standard rear door and head protection airbags. You can see the emblem “AIRBAG” on an E39 rear door embossed near the top rear portion of the door card, and you can see “HPS” (head protection system) embossed into the Alcantara on the c-pillar near the reading lamp. This was why I gave up looking at 2002 models when I was M5 hunting back in 2003 as I definitely wanted the head airbags, HPS, in the rear (family concerns). As a side note, the 2000 M5 only had the rear door airbags, not HPS.
For 2003 the Navigation system was upgraded to a DVD-based main unit which was faster and held the entire country on one disc vs region CDs.
I think that covers it. If anyone knows of other changes please chime in – all of this is just off the top of my head. Sorry for the long post once again, but I’m trying to make these succinct and failing I guess!