Originally Posted by Eclypz
agreed...
you've made no internal modifications to the motor, which would require tweaked maps. Since most generic chips are just set to dump more fuel in, you'd see your gas mileage drop for little to none performance gain.
I would disagree with this. Although it is definately a plus to have inner engine mods done, I have had a modified P28 ECU chip put into my del Sol Si which has little more done than a header and intake. The difference was huge! The car was way more responsive than ever and had a nice increase in power. This was, however, an Eric's Racing chip (not cheap). From what everyone said on TeamSolCal.com, that was of the best (and most expensive) ECU's you could get for the del Sol. I did not get to use it long enough to see how it would affect gas mileage though.