Bogey Jammer, I have 2 FBMs in my scene, but when i put a skin on one, it automatically goes onto the other one aswell and it ends up with the 1 skin streched over the 2 cars 
EDIT: I figured it out, you have to press 'u' and select "object & obdata & materials & text" for both cars

EDIT: I figured it out, you have to press 'u' and select "object & obdata & materials & text" for both cars