Corvette

Cheat mode:
Hold L + R and press Up, Left, Down, Right, Left, Right, Left, Right at the title screen. The word "Yeah!" will confirm correct code entry. All bonuses will now be unlocked.
j thompson.

All cars and courses:
Go to the options menu, go to "Change Name", and enter XOPENSEZ.
LOUISDESHULLO4.

Custom corvette mode:
Win all C3 career mode races.

Route 66 Challenge:
Win all C5 career mode races.
CJB523.

Hint: Never lose a race:
When losing a race or getting into to a wreck, press Start. Select "Restart Race" and the race will begin again, not be count against you.
ChristopherP1003.

Hint: Get cops off your tail:
When a cop starts to chase you, try to speed as much as possible or take a shortcut. With the 1978 Corvette 25th Anniversary, the cops will catch up with you -- try your best to get away from. Note: this will only work when you race one on one.
K64mustang.