i guess the only thing i wonder about is how much does that thing weigh? and if you get it actually going 50mph how do you stop with just ordinary bicycle brakes? 
The motor kit adds 25 lbs to the bike. Bicycle brakes do take a bit of time to slow you down. My next investment is disk brakes. Takes me about 1/2 block to stop once I have it wound out with those calipers I have on it.
As for the guy above that asked why the pedals if it has a motor. Cause you need to pedal to start the motor, and on very steep hills you may need to pedal to assist the motor.
I don't blame some of you guys for criticizing the whole idea... I got into the whole thing by accident (sorta) then found out how much fun it is and got the bug. And cruising past a cop, on a motorized bike, with no helmet, no license, no insurance is kind of a hoot