I used the hks rs intake on my old fc turbo for almost 2 years before it started developing dirty spots. I also have hks smf intakes on my Fd for 5000 miles now, still in like new shape. And I also live in Fresno one of the dustiest cities. As
Far as power increase, I don't need a dyno to feel the increased throttle
Response and increased high-rpm power. Hks is expensive but u get what u pay for.