doesnt your engine getting more powerful and free-er at high mileage means that its near wearing out? Dont know why you say you wouldnt be insterested in schrick as the easiest most cost effective way to get a power increase with NA is schrick VGI, schrick 268 cams and remap, filter and exhaust etc compliment this but those 3 are where your easy increases are. BMC CDA is the daddy of CAIs and they pop up all the time on ebay, i got mine for 50 quid I have read that SS manifold is only really for sound on NA as they only come into benefit with a supercharger, however true that may be. General c