I have a 87 GN and it is all stock except for a K&N filter. I have two ECM chips from my last car I owned (an 86) and I was wondering if anyone knows which I should use. I have a Hypertech P# 41372 which they still sell call the ThermoMaster, and a old ATR Pit Bull. The Pit Bull is the one I think is the best one but, I talked to them on the phone and the said I should sent it to them for a chip exchange to the newer one. The Pit Bull has this number on it.. HP137R-528SDL ... If I use the Pit Bull should I send it in for the chip exchange or does the one I have here now have any advantages over the newer one they sell? Any help would be greatly appreciated.