The M3 is working now. Not perfectly happy with it, but after modifying the transition and volume levels it will be good to go. I used six different rpm levels. Each level is recorded at the same engine rpm, so you don't have to know the actual rpm levels for the tracks, wheels, etc. I still have to read up on how FMOD does the transition from one sound to another so I can smooth them all out.
It took longer than I thought. I was hoping to release a small sample today, but there just isn't enough yet.