First, even if you cannot get the broken stud out with a reverse drill bit, you can drill and tap it for the next larger stud without removing the head.

Second, what is you time worth for replacing the gasket? An '88 740 turbo sedan is worth $500-1000 in my area and a wagon $700-1200...and that is assuming it needs nothing. If you have no reason to suspect a failed head gasket is a new one going to increase the value of that car equal to the value of the time you put in it?

Anyone buying and old turbo brick falls into one of three categories: enthusiast nut like us (in which case the reality of a 242K car is pretty clear), that wierd teenager who thinks a turbo is cool even if it is in a mommy-mobile, and people who only have $500 bucks to spend but kind of like the Volvo for some odd reason (if it is a wagon, maybe they need the cargo space). Only one of these three people will appreciate the value of the new head gasket and that person is one least likely to be turned off by a car that does not have it.

Onkel Udo