Hey guys, sorry I'm kinda new at this. My dad bought an 07' e38 1/2 ton gmc with th 5.3 and he wants it tuned. More power, maybe mileage? Anybody have any ideas, or maybe point me in the right direction? I have done an 01' 5.3, and a few duramaxes, but this truck I'm not sure on. Truck is stock. Any help would be appreciated.