I think it depends on a couple of things.
If you want straight line acceleration (drag strip, stoplight racing) then the RWD/LSD has a theoretical weight advantage of about 170# over the AWD. However 0-60 times seem to be virtually identical depending more on the track and driver than the powertrain configuration.
If you like drifting and cutting donuts in your company parking lot or showing off to the neighbors with clouds of burning rubber smoke, go with the RWD.
If you want to just save $2,000, it's RWD.
If you prefer handling on winding roads using front wheel grip to prevent excessive oversteer, go with AWD.
If you need traction in the winter on bad roads, AWD is the only way to go.
Finally, if the 167mph speed is important, you may find it more difficult to find an AWD with 19" wheels unless you get the GT2.