For the Bit Char-Gs, there are already a lot of body styles out there. You can get ones that are clear plastic and paint them yourself. Some guys have even gone and modified them by making them into drop tops or even added ground effects.
You can get slot car lexan bodies for them, which gives you an even larger range of car bodies to modify.
Finally, you can also get toys like the Muscle Machines and modify your Bit chassis to fit one of them.
Here's an example of what I did with a MM..
