I have always wanted one and this has been my project for the last year. I picked up a very nice running but far from perfect M5 with the intent of making a fun track day car. I purposely bought one that was not pristine so that I didn't feel bad ruining it : )
I have removed 350lbs by changing the seats, 6 pound trunk, removing all the audio, and sunroof. It really feels much more lively when I throw it around.
I also did a bunch of preventive maintenance / brakes / and a tune. The s62 is such a great engine, so much fun





My new audio system - bluetooth amp

 

Removing the weight and upgrading the engine and brakes will definitely enhance its performance on the track. I can imagine how much fun it must be to drive with those changes. Keep up the great work and enjoy every moment behind the wheel!