OK,
I am grad if I can help a bit,
yes I use the development SVM version, this is the one I compiles on OSX
I looked at all the engine sound files and found the following:
There are 4 different ones:
3S CS FE FF GT M7 MC MI RG T73 TL XS
AX2 CO M3 TC XG (XG had different envelop ?) XM
G4 (this one is stereo)
SB (nice one!)
can someone confirm this?
I looped them and also distributed them to the cars,
I put a tar file here:
www.cas.mcmaster.ca/~mohrens/sound.tar.gz
This was create using
tar cvf sound.tar `find . -name '*.wav' -print`
and is relative to the data directory.
So if you un-tar it there (data directory) it will overwrite all the engine sounds to the looped ones.
I hope this helps,
M.