to start off my father has been a service manager at a chevrolet dealership for 18 years, everybody wants to know if the tech2 will pickup the tune, the answer is no.Today my father and I hooked up the tech2 and went for a drive he checked every possible reading and not one reading was out of wack.This is proof that no dealer can tell whether you have a tune or not unless you tell them.This is something my dad wanted to know also just in case something happened to my truck before I sent my old pcm in, so now I will send in my old pcm.I hope this helps everybody who was holding out on getting a tune.Also according to the tech2 it showed 400 ft lbs of torque,I know it`s not a dyno but my dad said he has never seen the torque show that high,so he`s thinking atleast a gain of 35ft lbs or more of torque at the flywheel.The 6.0l averages 360 ft lbs of torque according to chevrolet.