What Dane said is completely true, but if you are not racing or if you are going to race in RCGT then you can use bodies that are more sports car style and are in a 200mm width. If you do that you will need to use offset rims. I use 3mm offset for the front and 6mm offset for the rear.
But if you are planning on racing in TC class then I would stick with dish wheels and a 190mm shell just like Dane said.
www.battlefieldraceway.com Racing videos at http://www.youtube.com/snoopyrc