Re: car body
I would research building a kit before you start, I built a Cobra 20 years ago and it was good fun with nothing more than an MOT at the end to satisfy the DVLA, nowadays though you have to get the car IVA tested before you can use it on the road, 40 page document full of rules and regulations that must be adhered to, check out a few of the kit car forums to see what i'm talking about.
If the racers don't need registration numbers I would stick to building them.