Knightshift: The car you have there is the C4 AGLE. THe differences between it and the C4 are:
-Longer chassis with the cells shifted forward on the left side(when veiwing from the rear of the car)
-3mm rear anti-squat
Thats a good car you got there. If you ever choose to, the upgrade to the C4.1 will only run about $149.00. But, that isn't anything you need to worry about right now. Just have fun with it!
Also, when considering a new body, consider the Vauxhall Opel Vectra. Its a really nice body.