I bought a K&N Power kit about a week ago and it runs great. It comes with the filter, outerwear, jet kit, and cleaning stuff. It explains everything from installation to cleaning and its real easy. I would deffinatly recommend this kit. Oh and I also ordered mine from Moto-man... or was it MotoWorld. I think Moto-man but either company sells it for the same price.

 

Actually that is not true, even with the pre-filter you still get better air flow then you would if you run the stock cleaner on it. A question for you tread; if Amsoil makes custom cleaners for most ATVs, then why would you have to modify your box? What kind of modifications?

I hear that Amsoil makes good products, but they are just too hard to get a hold of.

 

I've never personally had the EPA "air police" check the intake part of my quad motor let alone the exhaust, for noise, that's usually left up to the park rangers or maybe even occassionally a local sheriff.

In most cases if you just remove the lid to the air box it will give you enough air flow. I would rather do that then drill extra holes in the box. No matter what you do for extra air flow, as long as you re-jet it if neccessary you will be ok.