Hello Guys: One friend of mine owns a WR426 2002. We have began practicing supermotard, and he wanted to give his bike a bit more punch. He was considering adding a complete system with headers and pipes. What brand has a good price/performance ratio? How about kits which increase displacement? Bear in mind we are from Spain, so I guess european brands would be cheaper here. Thanks in advance, Jaime P.S. What kind of increase can he expect with the exhaust? And with the higher displacement kit?