Posada,

There are lots of threads on MCM about customizing the QingQi200GY. Do a search and you'll see all kinds of stuff!

DarkStar,

Hello and welcome. Feel free to introduce youself in the Introduction section. Where are you posting from? The 125's are very similar to the 200's. I'm not sure if you can put a 200cc top end on the engine since the case looks the same. Besides that, the power changes would be stuff like jets, pipe, airbox changes.

Generally, a 125 is a 125 and even with some changes there's no guarantee you'll have a much more powerful bike...sometimes it's worse.

CC