Is there any independent proof of these performance gains? I've see similar claims for many other vehicles that never deliver. Usually these things provide the same gain as washing and waxing your car. :^) In my experience it usually takes a much more extensive mod to get any real hp gain. With that said, I have had significant (measurable on a dyno) gains (on heavily modified vehicles) by removing restrictions in front of centrifugal superchargers. If it's just the sound you're after than it may be worth it.