Great buy! To speak about how solid these cars are: My Dad has two of these - an '84 and an '87. The '84 they bought in the late 80s with about 19K miles. He's still driving it daily, with A/C and all. It's probably been the most reliable car they've ever had. Mom has a '95 Grand Marquis (since late '95) and they've had alot more problems with it than the '84. The '87 still has about 70K on it and needs a master cylinder right now - otherwise has also been a great car.
I hate the top.Otherwise those are good cars,and really come alive w/a 3.73 gear swap.Mileage will stay pretty good,as it won't be kicking out of O/D so much.If the power windows ever quit,don't buy a new motor,it's probably those little plastic "cams" inside the motor that strip out.They are cheap to get,just takes a while to get the door apart to get to the motor & fix it(you will have to take the motor out of the door).Can't beat those cars for long trips.