Dear KeeJay,
"Which nobody cares about", you mean, you don't care about right?
Materials, you should try to fix your SLRR or enb if you use or maybe your gpu configs,
have you downloaded the HD envmaps or are you using generic ones?
The car has been tested in 4 computers here and all looks fine.
Customization, maybe I launch some update with parts...
The car wiggles at high speed because you are using steering help, turn it off!