I bought the kit and put the air filter in last year with my Rexxer tune and didn’t think much of anything about it. I got the air box out modified for the power up filters and installed over the winter and wow! The side filters make such a difference! In looking at the air box design I sort of feel the air filter isn’t doing anything at this point. Has anyone installed the side cut in filters only and seen a large improvement in noise power and satisfaction? Just spit balling the idea of others saving a few bucks on the main filter.