you asked about a shift kit. it will improve a lot of things about the way the trans works, but not necessarily things you will feel in the seat of your pants. the major improvement on the 4r70w is the pressure relief(to stop parts breakage) and the 4-2 kickdown is canceled from the computer strategy. i would use a transgo hp/hd shift kit. to tell you the honest truth, i don't know your abilities but i wouldn't recommend this as your first attempt to do a "reprograming" kit. you will be taking a drill to the valve body itself and one wrong hole or 1 size to big and you just got a $500 paperweight. http://www.transgo.com/products.php...d=131&countdisplay=2&start=0&addcountview=Yes just so you know, i'm am more than willing to help anyone, but if someone attempts something that i have suggested they leave to people more qualified, i will laugh in your face and tell them "i told you so".