I just got my HPtuners in the mail today, I have nothing but good things to say about it so far. I have an 05 sunfire (ecotec) with the hahn stage 2 kit. Since there was no open loop the A/F ratio stayed around 14.7 while under boost, obviously this is no good. After enabling the PE enrichment, my air fuel ratio is right around 12.0:1 under boost. I was looking around in hptuners to see what else could be done and i came across the Fuel cutoff while not moving and Fuel resume while not moving. Could this be used as a sort of stutterbox? That would be sweet. I was trying to figure out my injector constant, i know i have 32# injectors now, and my currnet injector constant is 0.17800. I was going by shifted's formula of Inj Const = .17800 * (x / 32) = new injector constant. what i dont know is X ( the stock injector size in #'s) does anyone know? thanks for the help fellas.