Hi guys new here... I have a 99 sierra 1500 4.8 with a whipple charger. It also has a 400 turbo which I dont like. It looks like all the original tranny plugs are there. So which tranny am I supposed to have? I have heard the 4l60e? Are all years compatible? Also I really need headers, any exhaust suggestions? I have always been a mustang guy so I am new to this sierra thing..... here is a pic.