It's all in the tuning when it comes to speed, power, and lasting cylinders. You can richen it to hell and get ANY motor to last past 5 gallons. Then you can do what I did with my first motor, lean the crap out of it, get a rediculous 50mph out of a DTX 18 and then fry the goddamn thing. Man was that engine screaming, HAH! I DEFINATELY pushed the RPM limit on that thing.