Instant victory (Japanese version)
At the start of a race, just after the starting countdown (when the announcer goes "3, 2, 1, GO"), immediately hold L + R and press A on controller two.

Full pause screen
Pause the game and press X + Y.

Instant Victory (American Version)
During the title screen push A+B then hold down the L and the R triggers. The screen will pause and push A+B+X at the same time. This will give you all the cars.
submitted by Xtreeme Racer MaN

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