Well.. I was planning on getting a Pro Circuit T4 and a K&N filter for my '99 Warrior.. I found a Pretty good deal on those things..So my father went up to the local quad shop and they were saying that a pipe and air filter won't change any of the performance and is a waste of money...My father was going along with them, i also found that hard to believe because my father has a few sports cars and loves suping them up... but wouldnt a pipe and air filter increase power?.. they also said it would have to be jetted.. I also thought that you dont necessarily have to jet it... Some response to this..

P.S. Maybe he's just sayin that and got me it for Christmas?!?!?!?! ahahah

 

I think your last line is the correct one
but the opinions of you dealer is another example of how little most of them know about their product. Actually the easiest and cheapest way to improve a four stroke's performance, not necessarily the horsepower, but the ability to use the available horsepower, is by means of a good exhaust system together with the required rejetting of the carb and in the case of the Warrior, a replacement of the pitiful filtration system the have stuck us with since the beginning.
If you do in fact receive your hoped-for Christmas present you WILL need to rejet. Your stock main is a 145. I would pick up at least two fatter jets. the 150 & 155. (Skip the 147, not enough difference to matter) and test with the 155 first. If you need more info on testing/plug reading, I have written a file which can be more explicit on the subject. If you'd like it email mefor it.