Contact JP Motorsports of San Diego. They have been the biggest Qlink dealer in the US for the XF/XP 200. They had a custom exhaust for the XF/XP 200 about 5 years ago; I think they were made by FMF. I might be buying a new one this week from them, and the head sales guy, ‘Smitty' said they put on a one tooth larger counter sprocket to get a few extra mph out of the bike. You can ask him if they carry those, as well as a smaller rear sprocket. In my opinion, I would even start with a new front and rear sprocket before anything else. Then play with the exhaust and jets.
http://www.jpmotorsports.com/m_default.asp