It is not anything even remotely related to Whizzer in any way, shape, or form. It is not a clone, a reproduction, or a knockoff of any Whizzer model. I am just being straightforward and trying to give you the right information. Furthermore, in the ad, the seller described it as a factory-built motorized bicycle (maybe not his exact words, but close enough). That is also misinformation. With the type of kit that is installed on that bike, there are no "factory built" versions available. It is simply a kit that the purchaser would install on a bicycle of their own after receiving it. There are some shops that will install kits on bikes, but they charge a labor fee, and "factory built" implies that the bike rolled out of a factory with an engine on it. This simply is not the case. Again, I am just trying to provide you with the right information. The seller told you some things that he felt would increase the chances of making a sale. Still, $275 is not a bad price for a bike like that. But if the bike is going to take the back seat to other projects, it may not run when you want it to. Any bicycle with any type of engine will require more frequent service and maintenance than any non-motorized bicycle. Also, with the chinese engine kits, they sometimes require a bit of tinkering and maintenance to stay running and working properly. No, some of the parts are not better quality whether you get them from one vendor or another. There are vendors that make or sell aftermarket parts, and most of the aftermarket parts are of much higher quality than the parts that come in the kit, but most of the kit parts are of a quality one might expect from a $150 engine kit (think about that). If you are willing to invest the time and most likely money, you will have a decent running bike. If not, your bike will sit undriveable more often than not. As far as going faster and stopping faster, I would focus on the latter first. Even at 25mph, strong brakes are very important. Once you get decent brakes or get the brakes you have working adequately for the speed you're going (can be done depending on what type of brakes you have), then start your performance mods. as far as lowering the bike, if its a 26", you can drop it an inch by going to 24" wheels. if you want to drop the frame, chop and weld basically.