Its going to very extremely hard to get low 12's with that truck,I dont care how much money you throw at it. It weighs to much,and with the 6 speed you'll spend to much time shifting,and off boost. If your lucky,you'll get in the low 14's. I would have a 2wd reg cab,stripped,auto,DTT work,all mods,slicks,+ LPG/NOS,then you might get low 12's consistently.