I'd recommend starting with a kit from ARC. They make a bunch of race car kits so just spend some time on their website. You'll help yourself a bunch if you sit down and list all the electronics that you'll be running in the car. The problem that most people have is they start off with just the obvious stuff then then start to add things like a line lock, two step, trans brake, etc. As they add stuff the wiring becomes a rat's nest.