Enter the following codes in the cheat menu to get the desired result:
YAYCARS: get all Cars and paintings
IF900HP: get all mini games and tracks
CONC3PT: get infinite boost
VROOOOM: fast start
MATTL66: get all art
WATCHIT: all videos
OLDY2D0: be Lizzie
MONAR02: be Monster truck 1
GOOGLER: be Monster truck 2
RACEKAR: be Flecher
PIXARFY: be Woody the Wagon
MCQNL94: be Mia and Tia
DUN33LI: be the 33 racecar
FRANKSB: be Tractor
PEACEOT: be Fillmore
CASEDEL: be Luigi
BOOTCMP: be Sarge
CHEATER: be Boost
MUSIC8R: be Dj
TORCHED: play on Fire