Well i've been reading on this board and CAI's are a very popular discussion on the HP increase, from what i understand MHP has a larger tube then injen, with a smaller tube like the injen the air flows faster, but this also will slightly increase heat. If i'm not mistaken the increase isn't that great either way, whichever u want go for it, will be close to the same and will sound awesome. i still haven't decided, but i'll probably go with the MHP b/c it will match nicely under the hood and it also comes with the bypass valve