thanks i just want to make sure but ill go with the stock method what bike did you have>?
I had a inexpensive bike like the one you are getting. I bought mine from Target a few years back. The spokes weren't strong enough to deal with the torque from the engine which caused some problems. There are hub adapters out there that don't bolt the sprocket onto the spokes and will ensure that the sprocket has minimal runout and proper alignment with the engine.
Also be sure to read though the threads that other 1st timers are creating. Many people have ran into some issues in one form or another and have asked or made suggestions for the resolutions to those issues. Some of the most common include problems with the cheap low quality hardware that comes with these kits - particularly the studs used for mounting the engine to the frame. Best thing to do is plan on just replacing the mounting studs and other hardware with higher quality parts. Too many people have ridden for a short time and all of the sudden the studs snap leaving them stranded a few miles from help or home.
Also while these kits try to be as complete as they can they are not exactly 'one size fits all.' They can't make a kits that will fit every bike so expect some customization. While some people just want to put that thing on it and go others take pride in the challenge of putting their rides together.
And as always, if you run into issues don't hestitate to ask someone here on the forum. Chances are more likely than not that others here have ran into the same issues and worked with others to help resolve them. Lastly, have fun.