Hi Otto. I've worded the previous post badly, the bike was already fitted with PCV, Motad freeflow exhaust, standard header and K&N filter so I didn't really expect a significant gain. For me, after reading the whole of the big gulp post I was impressed with the thought and work people had put in. As well as that the item looks factory fitted which I always like. l sold a K2 GSXR600 to buy this bike so performance was never high on the list but as others have quite rightly said before me, with these mods the bike now runs as it should have done out of the factory. I would recommend this mod to anyone and prefer it to the K&N because it was developed by people who share my love of this bike. Thanks again