well when i first put on my K&N i could feel adifference it was alittle faster and with the pipe it was alittle more faster. I think it sounded prety good with all the disks in it and then i took four out and it sounded like crap because the more baffels you have in there are the holes in them and the air went further out till it hit the spark arrestor and when i took the four out the spark arrestor was closer so i took them all out even the spark arrestor and its sound real good i felt it has alot more low to mid power it only cost 200 i justgot the slip on. I was going to jet it but the jet i got was a 162 and it was to big for some reason but they say the 155 stock jet is rich anyways so i just left it in it. It was to hard to get to the carberator.