Ok i just ordered an AEM cai from speed and style dot com. i also order the bypass valve. my question is this.. the bypass vavle that i ordered is the 3 inch one i wasn't for sure what size to get so i just got the biggest one. is there any reason behind the different sizes? thanks:D

you got the wrong size the size of the valve fits certian intake pipes. the size of an aem intake for our cars is 2.5 inches but if you got a different brand it may be bigger

I just got my AEM CAI yesturday, If you ordered one for the Non-Turbo you will need to get the 2.5, The 3inch will be to big.

While we're on the topic of the bypass valve, do you have to actually cut the pipe for the intake to install the bypass valve. I wasn't sure how you install that and that sounds like the only possible way.

On the new AEMs yeah you have to cut it. On the older ones they came in two pieces and it went in between. You probably got a new one.

I have the older style (2 pieces) but I still cut mine so the placement of the valve was in a better location. I think it's better that way rather than have it limited to where the pipes connect which I think is a bad location for it.