if you want to spend a little, buy a k&n filter... call it a day
if you really want to blow money on it... i think the best bet would be the cobb sf (only w the airbox). anything that changes the maf tube needs to be carefully designed. they've shown the air to be cooler with their intake, but that is not really going to correlate the same way to power output.
spt i think is metal and if i recall correctly people complained of it getting burning hot.