I've got the K&N cai. It requires no mods, direct bolt on and go. It looks pretty nice with the polished tube and the K&N never needs changed so it's good for life (supposedly). It sounds great too. Oh and best part is you can get one brand new from Ebay for around $50-60 for the whole kit. I think it shoulds about the same as injen or stillen but way less cost.

 

where in the hell did you find a nismo intake for 50-60 bucks on ebay? they go for about 280..

do you have pictures to prove that its an authentic nismo intake?

some kid last week had a pop charger that he thought was a nismo cai

edit: and iirc, isnt the nismo intake tube black? or maybe they came out with a polised one too..but i doubt it

 

Thanks for the different perspectives. I am under the assumption that sound would be the only measurable benefit, but I am ok with that for now.