Here it's a cool cheat that lets you to play with any car in any level you want!

Note: You need to have game complete 100% to do this (that means all missions completed not skipped, all cards, all cars bought, all costumes bought, all wasps, all gags and more + the bonus movie at level 3 after collecting all 49 cards)

once you completed the game, go to options menu, hold f1 and press up down up down (this is the cheat for PC)

once you entered the cheat, go to phone booth. press f2 and then it will appear a list with all cars from the game including all unlocked cars that appear at phone booth, all bonus cars (speed rocket, monster truck, rc car, etc), all street cars, all hidden game cars/unused cars (ice cream truck, cube van) and more...

you can use any car in any level you want! it is worth to complete the game 100%.