Re: 2 or 4-stroke
I've had several two strokes and am looking to try my first four stroke this fall. I think you need to do some self evaluation... money tight? 2 stroke kits are less expensive unless you want to spend a bunch on aftermarket upgrades... jackshaft kits and expansion chambers, etc. The 2 strokes look better in the frame and take up less room, so some bikes can accept a China Girl when there isn't enough room for a four stroke if you want to go in frame. As Pablo said, the China Girl was designed for a bicycle. How mechanical are you? Or how mechanical do you want to become? Some people just want to get in their car and turn the key with no interest in how the car works, learning to change the plugs and oil, changing a tire or maybe even a little mechanical work... brakes or clutch perhaps. 2 strokes take a little more maintenance (I am told) which for some is a pleasure and for others a pain. I think some of the people who get a bike kit and don't want to do anything to keep it in good order would have done better to get a Chinese scooter or just drive the car. Bikes with motors are kind of primitive machines which appeals to me and is part of the allure... like the early motorcycles. Having your own bike of your choice & motor which you put together can be a great satisfaction and a reflection of you. So, don't just look at what was right for somebody else, but do a self check and go from there. You can always start out with a 2 stroke sticking to a pretty tight budget and later move on to something better for you if you decide it doesn't suit you or your money situation improves. A basic, bump start manual clutch 2 stroke is fine for a young person especially. Some of the older riders want a pull start and an automatic clutch, little maintenance, all of which comes with a price tag. Hope this helps.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...