Rick, the ride on the 'vette rear is adjusted by spring rates and shocks. Narrowing isn't that difficult. It uses two short tubular driveshafts on each side that any driveline shop can handle. I don't recall how the lower arms are made, but they would be the harder part to narrow. Have them cut and welded, then have the same amount shortened from the driveshafts. Mounting isn't that hard. You need a crossmember with a plate that the center diff bolts to, then a mount for the lower radius rods.
Is the Corvette diff a Dana 44? You might be confusing it with a Jaguar IRS, which uses an English version of a Dana 44 diff (there are some differences). The Jag axle I'm more familiar with. The main differences is that Jag uses a tubular lower arm (easier to shorten), forged half shafts (small diameter, harder to shorten!), and four coil over shocks. The forged shafts are used due to the narrow space between the shocks, but the shocks can be spaced out further and small diameter tubular shafts used. The u-joints on both are standard GM parts. The 'vette axle uses a leaf spring anchored on the cast diff cover. It's more complicated than a straight axle, but the ride and handling are appreciably better with the 'vette or Jag axle. The axle will weigh a little more, but most of that weight is sprung.
I have a Jag axle in my Rambler. It was pretty straight forward to put in, and a 'vette axle would install the same way. Take a look at my album. You'll need to make a crossmember similar to mine. Just take a look at a few stock installations and brace yours accordingly. I used a pair of four link bars with poly bushed ends for the radius rods. No spherical rod ends! Those beat loose quickly on a daily driven vehicle. Of course with the 'vette you'll need to make mounts for the stock radius arms. (see pics at 20car.com/specials/corvetteirssm.jpg)
It wasn't that much work to put the Jag axle in my Rambler. It was a lot of work to rebuild the axle. If you have a used axle, make sure you replace all the seals. The 'vette isn't as bad as the Jag about cooking the seals since it has outboard brakes compared to the Jag's inboard -- right against the diff. But the whole thing has to come out and apart to change those seals. Do yourself a favor and change them before installing! Change the outer seals and repack the bearings before installing too.