some helpful info

at the start pick the miata

codes to enter at the title menu
Unlock Visual Level 1:
R1, R1, Up, Down, L1, L1, Up, Down.

Unlock Visual Level 2:
L1, R1, Up, Down, L1, Up, Up, Down. Unlock Performance Level 1:
L1, R1, L1, R1, Left, Left, Right, Up.

Unlocks A Hummer H2 Capone:
Up, Left, Up, Up, Down, Left, Down, Left.

$1000 in career. RX-8 and Skyline in Quick Race:
Left, Left, Right, Square, Square, Right, L1, R1.

Unlocks Nissan Skyline:
DOWN, DOWN, L1, L2, L1, L2, L1, DOWN.

All Circuit Tracks:
Down, R1, R1, R1, R2, R2, R2, Square.

Unlock Performance Level 2:
R1, R1, L1, R1, Left, Right, Up, Down.

Burger King vinyl:
Up, Up, Up, Up, Down, Up, Up, Left.

Unique Vinyl Down, Up, Down, Left, L1, L1, L1, Down.

Unlocks the Best Buy car Vinyl:
Up, Down, Up, Down, Down, Up, Right, Left.

$200 in career:
Up, Up, Up, Left, R1, R1, R1, Down.

Unlocks the ShineStreet Lexus IS300:
Up, Down, Left, Up, Left, Up, Right, Left

If you have more Q's I will happily help you