Just thought i would let you guys know i installed the factory pro advancer (+4) this weekend. Most say it really doesnt do anything but i must say its not in my head but it does throw a little bit of umph in it. Revs of hell of a lot faster thus getting me where i need to go a tiny bit quicker. for 50 bucks worth it to me. hour and a half to install (ya i know its long but that damn gasket material took me an hour to scrape it all off with a razor) but in the end worth it. Only negative is the motor does run hotter but i could live with that being that its liquid cooled