Thanks for all that info, it helps!
I've read about numerous people having their stock clutch setups last over 100k. I suspect I could easily be one of those people since I never dump the clutch, I don't drag race, and I don't take it to the track either. For me it's just a fun weekend car that we take on long highway trips and what not.
However, it does sound discouraging that the same clutch is used in the 540i which has significantly less horsepower. There's two clutches I'm looking at (aside from stock) and those are as follows:
ECS News BMW E39 M5 South Bend Clutch Kits - K70282HDO - Stage 2 Daily Clutch Kit - ES#2725258
FX Racing Stage 2 Rigid Clutch Kit 2000-03 BMW M5 E39 Z8 E52 S62B50 4.9L V8 DOHC
Now, the Gripforce clutch is significantly cheaper and seems to be rated for higher horsepower than stock while still being a good street solution. I question the cost of some of these aftermarket clutches as I suspect some of them are made by the same supplier just branded with different names and therefore higher prices. I know this is the case with automotive batteries. There are only a handful of battery makers, but once they apply a brand name to them they sell them for more regardless of if they're made by the same manufacturer.
I'm just going to go with the LUK DMF flywheel (the stock one). I found it for $387 brand new which is a good deal. My car has 165k and while they are all easy miles, I know it's the stock flywheel in there so any attempt to resurface it would be pointless when I can get a new flywheel for such a cheap price.
I guess all it comes down to now is the clutch. I have no big power plans for this car. I plan on getting an Evolve Tune, Evolve headers, and maybe down the road some Shrick cams and some headwork. That's it though, I won't go beyond that. So, in the end I suspect my car would never see more than 400rwhp (with all of those mods) on a very good day.
Remember, just hp is not that hard on a clutch once you are moving. And if you heel and toe (rev matching) when pushing the car, you take the strain off the synchros.
I think the real weak link in the stock setup is the self adjusting mechanism (SAC). I suspect that if you replace the pressure plate and disc without the SAC and you are an intelligent driver, you will be fine. At under $400, I would get the new DMF.
As to power plans, if you get to 400 at the wheels, that is basically Dinan S2 level, about 470 at the crank. That is pretty healthy.
I am pleased with my CNS notwithstanding the questionable marketing practices. It does not take away from the quality or design of the product.
Dinan Stage 3 suspension, SS jet coated headers, ESS SC kit w/ 1 range colder NGK's, 92mm pulley, 440 Big Greens, TTFS alpha N tune for meth, RK plenum plates, SBC Endurance Stage 3 Kevlar performance clutch setup, "Jed" lightened DMFW, open brake ducts, TEC cupholder, U.S.(Euro style) tilt/slide armrest, 6k HID fogs, Umnitza bi-xenon flamethrowers w/6k super white low beams, rear fogs, V1/Stealth1, dual head LI, 2.65 diff w/40% lockup/2x dynamic, compact spare, M5 logo trunk carpet, Euro trailer hitch, Mocal oil cooler, ACS type rear spoiler, Rogue custom SSK and tranny mounts, ST 355 BBK (fronts), BP sway bar brackets, Bluetooth retrofit, Speedhut boost gauge (20 psi), Dinan TB's and VS, KB BAP, Howerton/HFS-3 Aquamist WI trunk setup (50/50), with 2nd gauge in rear view mirror, aftermarket trunk mounted sound system integrated into stock unit (amps, crossovers, sub and speakers).......