When you beat a champion you will unlock their car and a new set of character parts. The Time Trial Queen is unlocked by beating ALL of her ghosts in Time Trial mode.

Unlock Capt. Redbeard, Gov. Broadside, Blackjack Hawkins, The Admiral, Pirate Car Set:
Come in 1st place on circuit 1.

Unlock King Kahuka, The Islander, Tribal Car Set:
Come in 1st place on circuit 2.

Unlock Basil the Bat Lord, Willa the Witch, Sam Sinister, Horror Car Set:
Come in 1st place on circuit 3.

Unlock Johnny Thunder, Pharoah's Mummy, Nova Hunter, Desert Car Set:
Come in 1st place on circuit 4.

Unlock Baron Von Barron, Achu, Jungle Car Set:
Come in 1st place on circuit 5.

Unlock Gypsy Moth, Alpha Dragonis, Alien Car Set:
Come in 1st place on circuit 6.

Unlock Rocket Racer, Rocket car set:
Come in 1st place on circuit 7.

Unlock Veronica Voltage, Lightning Car Set:
Beat ALL of the Time Trial ghosts.

In 'Build' mode create or edit a driver. To activate the cheat use one of the following names

No driver: NDRVR

Maintain speed off track: NSLWJ

Shooter attacking power-ups only: PGLLRD

Power-ups always at maximum: MXPMX

Mine power-ups only: PGLLYLL

Turbo power-ups only: PGLLGRN

Grapple power-ups only: RPCRNLY

Rocket car: FLYSKYHGH

Reversed Rocket Racer Run track: LNFRRRM

Disable all cheats: NMRCHTS