Stay away from the K&N filter. The way it gives you more air is by NOT filtering the air as finely as a standard filter does. Meaning that more dirt will pass through the filter instead of being stopped by the filter. This will lead to premature engine failure. It may not happen all that fast but it does happen. For me I would rather have a longer engine life than power. I have tried a K&N filter and learned from a friend about the problem and found a web site that show by comparason the quality of air that is filtered. On my K&N filter I had I looked through it at the sun and could see holes in it. I threw mine out and will never ever use or recommend K&N to anyone. You may try AMSOIL website and look at their airfilters. I have not tired them but their technology is impressive. On the other mods you mentioned, them I have not tried. I do use the "Tornado". I cannot say that I have seen any inprovment with it verse with out it. Maybe a mile a gallon inprovement is about all.