Game crashes when you edit Group C mods to be in the same class with Group C originals

I recently edited the cdr file to combine Thunder flash's GTE cars with the GTE originals and that worked perfectly.
I get a mixed grid with both sets of cars.

I then, decided to be a smart arse and try and combine the group C category cars but im getting the bug splat crash when i select one of the Group c Mod cars For a custom race. When i select a Group C "original" car and set up a custom race, the game doesn't crash but none of the grpup c mods are selected on the grid..can anybody tell me where im going wrong here?

 

Also renamed the Group C mod to Group C but i can choose and drive all three mod cars without issues.Maybe doublecheck your crd.

Also get a mixed field of all 7 cars. Maybe an issue with custom names/custom AI

 

Thanks bro, im gonna give that a go...i might re-download and re install the mod for belt and braces...