I added a Walker 22844, similar to the Donaldson M090146. It's huge- I had to remove the heat shield & MG ring mount bracket to fit it. I added a bracket attached between my hardtop & windshield frame to take some of take some of the stress off the exhaust, as the stock pipe bracket doesn't exactly fit...
The truck came with foam insulation in the cab & ha fiberglass hardtop. C-D turbo swap, Monster Muffler & foam strips around hood & side panels. Next up, bolting down the loose PS fenderwell at the frame & insulating the hardtop. Truck's already quieter than the CUCV, until you walk in front of the radiator. I can hear the turbo spooling between shifts now.
For normal people, the next step down is a good choice. If you want to try making a Ninja Deuce, this or rear exhaust with bigger mufflers is a start.