WOW your getting 17-19 on the road with it set mild. My 2000 gets 24-26 around town and set to the most agressive point I can get it. I don't know then, I can tell you this I normally run mid grade gas in the car and after I adjusted the bypass I had Detonation that I never had before and had to go to 93 octane to get rid of it. I can definetly feel the power difference in my car. Maybe just maybe yours was not out of adjustment nearly as far as mine. You never know until you check. I do know this, adjusting the bypass to get a little more boost was far easier than changing out a blower pulley and it was free.