I have a complete stock 2008 XT660X. Just removed the snorkel on it,didnt change anything else and must say that there is a noticable diffrence in performance gain. Not much,but in the lower revs it pulls slightly better. Am gonna order the stage 1 & 2 aircleaners from OTR now. Still waiting on the MTC 2into1 exhausts to be available. Have just tried to order the KEV fuel mod from the forum but I can't seem to get my paypall account registered...

Anyway... You can definatly feel that there is alot more power in that engine than the way it rides coming from that factory floor...
Why don't they make em with good filters and exhausts stock???
But then again... You won't have the fun of modifying it yourself.