I bought a 2010 Z71 Suburban back in February (E38 ECM). I'm looking to do a mild tune on it, because I drive a twin turbo Duramax with EFI Live tuning everyday, so the Suburban just feels too slow. I don't plan on changing the exhaust or intake, I just want a nice tune for decent street power and mileage. I'm new to tuning and the guy who tuned my Duramax I don't think messes with gas engines. Can anyone give me some good starting points? And can Onstar tell if I have loaded a tune into the computer?