I have no doubt the newer karts have innovations that make them moderately superior to the one you chose. Still, when it comes to handling, most say "tires tires tires tires". An engine, properly built, can make a difference, so stick with the box stock class. Right out of the box. The Briggs LO206 is a good engine/class to start with. I say that because your going to spend so much time learning to drive and set up the kart, worrying about somebody building a better engine is something you might want to avoid, at least until you learn the basics and your kid gets comfortable racing. It might look easy, but I can assure you it's not.