i have hptuners, i originally bought it for my sub and silvy, but now i sold both. so i use it on both trailblazers. but i don't see much of a difference. i firmed the shifts up, and took some torque management away, but i don't know what to adjust as far as trying to extract more horsepower. i mean i know its all about spark and fuel but what exactly should i adjust. and on the TB ls i6 theres no a/f to command. i bumped that up a tiny bit on the SS. anyone that uses hptuners, any info is appreciated. i have gone to the hptuners forum but those guys are way out of my league.