I will also add that when I first installed my Stillen Gen3 intake (stock exhaust/cats) it had a very noticeable growl throughout the RPM range, obviously being louder in the higher RPMs. It was awesome. After about 2-3 weeks that additional low-RPM growl was pretty much non-existent, so I assume it took a week or so to settle/burn-in.
Definitely a good first-mod because if you add it AFTER an exhaust you won't hear it at all in my opinion. With my CBE/HFCs there's no way i'll hear the intake even at 7k+ RPM
