I've been wanting to get my 5 yr old son involved in RC with me as well. I bought a used Tamiya Dark Impact 4wd buggy that I had him try out a few times, but it's way too fast for him right now as he doesn't have good throttle control yet. I would advise against a 2wd buggy just because it takes a lot more precision to drive it. If you want to stick with a buggy, get a 4wd rtr Kyosho ZX5 or the HPI Brama 10b rtr.