IIRC in the past those who have looked into chips/tuners found thet our engines perform pretty close to their limits and the price of the tuners was not worth the little gains that could be achieved...of course this was on a non-modded engine. As far as just getting your speedo correct...there are several devices that recalebrate speedo or you might check with your local speed/tuner shop. I know there are a few in my are that recalebrate speedo's.