it's a ton of fun, trying to get my Kt-100 out to circlevile as soon as i get a chance. as far as picking out a kart i would recommend getting a tag cart, i prefer Rotax engines. I may only have $400 in my Yamaha, but i had to rebuild everything, and they're a much lower build quality, higher maintenance. shifter carts are cool, I've only done a cupple laps but it is more to learn shifting wise but your brain as to work much quicker due the increased speed. As far as I know circlevile only has 4 strokes for rent, they MIGHT be just a little faster than speeds karts, I wouldn't recommend even trying it. My buddy is selling a 07 kart mini w/rotax TAG package, (50mm axle) kart stand, mycron 4 and a bunch of other stuff for $2500 i think. PM if your interested.