My personal opinion is get one with a closed box or one that snakes down where the stock washer bottle is. I personally do not like that the open boxes rely on the hood to seal up the box. I know there are a couple having sealing issues, but I don't recall which ones were having the problem. Research is your best bet. There are TONS of threads on here about the pros and cons. In the end they will all make roughly the same power. Me personally I am looking at IAT(intake air temp.) I will be looking closely at this when the
V8 Jannetty Cold air testing is done.
http://www.camaro5.com/forums/showthread.php?t=88637