Yes, I am planning on showing the car (eventually!) and my goal from the start was to get it as perfect as I possibly can. So that means I will more than likely go for the new driveshaft, rebuilt original u joints and restored slip joint. And BTW-Thanks to everyone on this site for the expertise to make all this possible.
The last Mustang I did was a '65 coupe way back in '78. A LOT has changed since then!