Nothing has gone wrong yet, but I suspect that in a few hundred miles the started and the A/C compressor will need to be replaced. When I start it up it usually takes a few turns and sometimes when I put it into reverse or drive it stalls.
Other than that, I with it had more get up and go, but it is a non turbo, the car weighs 3000 pounds, and to my surprise it actually out accelerates my past 2003 Ford Taurus. The only other thing that peeves me is that when I am slowly accelerating from a cold start there is a little bit of metallic noise during gear changes and from the exhaust, but that goes away. And I can't tell if the previous owner has changed it to r-135 *4 cooling liquid. I bought the car for $2600 from a local owner who had taken very good care of it. The car is 16 years old, so things, especially the plastics in the interior, are starting to get brittle (hazard light button, third taillight cover, seat belt buttons, door pockets, a-pillar shrouds, driver side lumbar adjust screw (yeah, the big white one in the seat), but that and the rest of the maintenance is acceptable for a Volvo and the cars age. After all, a fine machine needs fine maintenance. I can easily see this car lasting me until at least 300,000 miles.
I have a 1990 740 GLE- have had it for 6 years. It is an excellent car, drives well (if a bit slow) and is really comfortable. It does need reasonably expensive maintenance sometimes, but so do most cars. I was in an accident once and it was amazing- hardly any damage to my car and a lot to other car... definately a very strong vehicle! Go the 740!
I also have a 89 740GL and I get a metallic noise as well at about 2000-2500rpm. Have you been able to find out what it is?
If you have please email me at listen69@gmail.com.