I'm not sure how much difference a Olds vs. Buick would be. I think they are pretty much the same animal under the skin. I could be wrong.
We got our 98 Intrigue from wife's Mom.......dealer maintained and purchased a couple years ago when it had around 78,000 miles on it. Has about 95,000 on it now.
The more I drive the car, the more I like it. Have had zero problems with it, the 3.8 liter engine (love this engine!!) gets easily 30mpg on the freeway, and it goes down the road like the Queen Mary. In town, the mileage drops off quite a bit, but I use the car pretty much all on the freeway, anyway. Set the cruise at 70 mph and it's still pretty quiet on the inside.
What is it worth? I don't know. Tell him the mileage is a little high and you were really looking for something that gets better gas mileage. Take cash and he'll come lower than 2700.
Good luck. Hope this helps.
vmax84