I have a Doug Nash 5 speed in my car with the deep first gear and 1:1 fifth gear but those transmissions don't really fit in a Mopar. Besides not fitting, they are clunky and loud and generally a pain in the rear.

The Passon is a good compromise for a car like this. It is probably 20 lbs heavier than the trans that is in the car but the weight is close to the CG so it shouldn't upset anything. The driveshaft speed is just one thing to deal with. Carbon fiber shafts are expensive but certainly not a deal killer. Just part of the price of having a 150+ mph street car.

With the 3.91 gears the car will probably run mid-elevens at the drags. It isn't set up for drag racing but with those gears it would get out and go.