Do It Yourself Dune-buggy What Kind Of Go-cart/dune Buggy Should I Buy?

What kind of go-cart/dune buggy should I buy? - do it yourself dune-buggy

My wife and I together weigh about 400 pounds. I want a good acceleration. Like a little engine work done? Automatically or manually, or up / down / around? And who? What he street legal? The importance of a problem or are relatively easy to fix yourself? Or should I go with the crowd and just get an ATV?