Oh man, I've got the same options as you. I just can't bring myself to tear it apart to make a dedicated track car (yet), so I'm looking at getting an e46 M3. At least the leather in that car is 8 years old, so it's easier on the stomach.
Please post pictures when your car is finished. Is your car just for HPDEs or is going to be a race car?
"The laws of physics cannot be repealed, even with DSC." - BMW Owner's Manual