I raced 100cc for three years... too years with can exhaust and one year with pipe. This year I ran a 125cc... less maintenance and more power! I haven't been in a shhifter kart yet, and I don't know that I will ever own one but I'd like to take a ride sometime. They are quite high maintenance and beat your body up something fierce. Anyways, it's one of the cheapest forms of racing you can get into.