well you need to go with allens hot tune..it's the 93 octane tune with all the torque managment deleted...he can fix your speedo so its right as you have bigger than stock tires...shift points and firmness of the trans also...you want your moneys worth..get this one...it will also get you more mpg as it did with almost everybody else...you will be very impressed with the tune..guy here had the dual tune and changed it for the hot tune in no time...
'13 silverado LT...stock
'11 lt 4x4 z71..tvs1900
'01 gmc twins 6.0 jakes 400 ladder bars w/ coilovers tuned by nelson performance