Unlock All Cars:
Enter hotwired as a case sensitive cheat code

Unlock All Cities:
Enter theworldismine as a case sensitive cheat code.

Infinite Nitros:
Enter zoomzoom4 as a case sensitive cheat code.

All car abilities:
Enter greasemonkey as a case sensitive cheat code.

Most dedicated stat:
Enter bigbrother as a case sensitive cheat code.

Missiles and Machine gun:
Enter lovenotwar as a case sensitive cheat code. Press Right Analog for missiles and Left Analog for the machine gun.

Change difficulty:
Enter howhardcanitbe0, howhardcanitbe1, etc to howhardcanitbe9 as a case sensitive cheat code where howhardcanitbe0 is the easiest difficulty and howhardcanitbe9 is the hardest.

Change game speed:
Enter howfastcanitbe0, howfastcanitbe1, etc to howfastcanitbe9 as a case sensitive cheat code where howfastcanitbe0 is the slowest and howfastcanitbe9 is the fastest.