If you go with a 3.8, just go with the big auto from the 3.5 in the SR and sports. The 5 speed auto is what I want but the control is Canbus so one needs to get around that.
The control for the 4 speed is simple to work with. It still uses a cable for throttle pressure.
Plus the super select may be wanted since you should be up in the 400'lb range. that could put a hurt on the rear tires.