Taylorboy

I Understand on the weight of the tires etc.. I’m not trying to break the bank and definitely not trying to dig into the motor as far and cams and stuff what I’m asking is?.. What would be best for better gas mileage (tuner or programmer) and still have enough power to get up and go when I need it to. Really would like to go faster than 99mph what could I do to turn that function off?

Just bought a 2015 gmc 1500 crew cab 4x4 and was wondering how to make it faster? Any ideas