Right, but sleds can be had cheap also, and if you get the whole thing you also get shocks, hydraulic disc brakes, and tons of very useful nuts and bolts. I've gotten a few free parts sleds, and when i take them apart i keep all the nuts and bolts, i cant tell you how much time and money i have spent by using them instead of going to the hardware store every time i need something.
I'm also torn between making a shifter kart, or leaving the cent clutch and tecumseh engine, i'm looking for the easy to drive thing also, because if i ride it with friends, i know the shifting is going to be a problem. Plus a lot of people dont understand they cant just keep it redlined.
anyways, my vote is sled engine.