Originally Posted by Craig

10. ANY bumper stickers or decals (especially those "fish" things).
11. Non-stock tinted widows.
12. Chrome fender arch covers (usually used to hide rust/dings that the owner is too cheap to fix).
13. Any wheels that are noticeably larger than stock.
14. ANY non-stock chrome wheels.
15. Satellite radio receivers on any car too old to have a factory satellite radio.
16. Those little rubber aerials in place of the correct retractable unit.
17. Broken radio aerials that stay up when the car is parked.
18. Any headlights that do not at least appear to be US or euro OEM.
19. Clear fog lights or models that should have yellow (and the opposite).
20. Basically anything that doesn't look like it came from the factory.

That's just the exterior stuff, I'm not even going to list the defacing you can't see (after-market air cleaners, weird VWO conversions, etc.)