In the options menu hold L + R and enter the following:

Code - Effect

Y, Y, X, X - Blow up vehicles in one hit
X, X, X, X - Faster cars
Y, Y,Y, Y - Fastest cars
Y, A, Y, A - Infinite car health
X, X, X, Y - Press horn to do a huge leap in your car
B, B, B, A - More camera angles
B, A, B, Y - Grid mode
A, B, A, B - All reward Cars
A, X, X, Y - Credits
Y, Y, B, X - Speedometer display
B, B, Y, X - Red Brick Car
Y, B, Y, B - Tripping mode
A, A, A, A - Night time mode