I think I just figured it out, I modded JUST the cameras and IK's of 15 different cars, one at a time, and didn't have a problem.
BUT.....as soon as I changed the physics of a SINGLE car to 4WD, the game crashed, I tried changing 3 different cars to 4WD in three seperate tests, and changing the physics crashed it every single time.
I went back to the default DB file, then changed the physics and the game ran fine.
I changed the cams and IK's of the following cars.....
Alfa Brera
Ascari KZ-1
Aston DB-9 Volante
Audi A3
Audi S6
Audi TT
Edonis
Caddy Cien
Caddy CTS-V
Caddy XLR-V
Camaro Z28
'71 Vette Stingray
SRT6 Coupe
Farboud
Ferrari 308
I changed the cams and IK's of all those with no problem, but when I tried to change the drive type of the ME-412, the SRT6 Coupe, and the Farboud to 4WD, it crashed the game no matter which one was chosen.
Physics changes by themselves don't seem to be a problem.
Camera and IK changes by themselves don't seem to be a problem.
But combining physics + cam and IK changes crashes out.