The manager of the 4wheel parts on the east side (east Washington St, near Washington Square) was a friend of my nephew, so when the 7" rear diff blew on my BII , and I wanted to swapp in the 8.8, I thought I'd give them the business, since I was pretty busy at the time.
I prepped the axle, gathered all the necessary parts, and had it towed to their shop.
I told them that I needed the truck for a job I was going to be starting, and they said that it would be no problem to get it done in time.
Ever heard that before?
Well,I called them the day before I was expecting to pick it up, and it turned out that they hadn't even started on the job!
After I chewed a couple of guys a new one, I finally got the truck back, but not before I had to rent a truck.
Now, I will say that they did a good job.
The welds were right, and they even welded the diff to the axle tubes.
They also had the driveshadft modified by a great shop for little more than the cost of materials.
That was 4 years ago, and 100,000 miles, and it's still doing fine.
Like the other posts here say, shop online first, and if yoiu happen to be in town, call ahead and see if they have it in stock.