Ebay CAI's work the same, if you have a 2001-2004, you have to get something to plug an extra hole in it, and if you live in California, you have to put the stock intake back on every Smog test. K&N, Mac, BBK, etc all have CARB numbers so they will pass testing. Other than that, it's not 6hp peak gains, it's just at some point on the dyno, there was a gain of 6hp, which for my car that gain was on the lower end. Actual peak hp was barely even higher.