I am not a big fan of K&N, I think that let too much dirt in and they are quite expensive. Anything that flows more air is also going to flow more dirt, it only makes sense. They are not really a good idea for a quad that is going to see any type of water or mud, they will become mushy and will allow water in the engine easier than a good foam filter properly oiled. I think they have the general public fooled on how good they are? It makes me laugh when I see a commercial on TV, they say they are the best air induction system money can buy but they don't say one word about filtering qualities? I would go with a foam UNI or TwinAir and even the stockers aren't bad. Just remember to clean them properly(foam) and use foam filter oil after they have dried...Irv