HOW MUCH for NEW GEARS INSTALLED?

Guys.........

I just got an estimate for a set of Yukon 3.23's installed in my 489 case and properly set-up, "in the car".......My gears are just too noisy for words.....as a matter of fact, I have words with 'em every time I take the car out of the driveway.

They quoted me $850. in the car......(specialty shop...drivelines only)......I nearly fell outa' my chair........

Is that a reasonable estimate ???