After waiting so long for the FIPK to be released, there has been little discussion of it's performance benefits. I would love to put one in my X, but so far I am not convinced that it is worth it. Whaddya think?

Happy with mine, I could feel the difference, which I was not really expecting, plus we picked up about 1mpg on average. Installation was a snap. I also like the engines sound, and it makes it easier to judge engine load. Wanted to get it dyno'ed but no one in town has a working dyno so... oh yeah, I think I'm supposed to tell you to do a search rather than answer... damn...
MV

Did a search. I was hoping for some more definitive opinions. Thanks.

Ruger1022 do you have the stock exhaust?

I installed a gibson exhaust awhile ago and didn't notice much performance gain, but i do like the sound a lot. Then just two weeks ago i got the K&N FIPK and you easily notice a different. It makes the exhaust sound even better too, and it just makes the Xterra seem to be a bit more responsive.

Still stock exhaust, looking to change later this month. I have asked and suprisingly got few opinions, I'm thinking of just getting a muffler rather than a catback system, as my curves, tees, and pipe size aren't bad. Just losing the weight from that monster of a muffler should help. Installed muffler for less than $100 vs. install myself (and how exactly? I have no bolt together joints after the cats?) for $250+? As soon as I do I'll let you know how it turns out.
MV

I've got the Gibson exaust and my own fabricated air intake. Throttle response did improve greatly and 2 m.p.g. on average. The pictures are on a previous post in mid May under custom air intake. A few modifications have been made to the support that holds the filter up, instead of the wire tie to the bracket. Nothing but positive results and sounds GREAT! If your interrested drop me a line. But to get back to the original question, I have no input as far as the K&N.