would you buy $10 sunglasses just because they are a "cheaper alternative" to oakleys or bausch & lomb? why on earth would you do that to your eyes? same goes for the car, i think. injen did its research, they are a company who backs up their products, and they have dyno numbers to prove things. so between the CAI and the SRI from AEM, i chose the CAI because of the way it looks, not because it performed better. i know i'm paying for a name, but that name reassures me it has been tested and proven to work.
if you really wanted to go cheap, you could go to home depot and find all the parts you are looking for for about $20 plus the cost of a generic cone filter from pep boyz for $8. why spend $40?