I bought a used K&N Typhoon for $270 and I'm really happy with it, it was on in 30 minutes without any issues. One of the members did tests on here and found the K&N heat shielding worked great and the filter was seeing temps barely above outside ambient while moving. The best intakes are the ones with the shortest piping that still pull in outside ambient temps.
As for the sound... holy moly, it's loud, all the videos I've seen don't do the sound justice. The people that are saying it can be as quiet or as loud as you want are not telling the truth. The only way to not hear it at all is to accelerate at the rate of a 1986 Yugo. You will hear it with normal acceleration, slightly to moderately aggressive driving it will be loud, full throttle it actually quiets down, but the BOV will be pretty loud whenever you let off. I love it, I won't lie.