1989 Mark VII LSC

Yeah, I know it's not a Mark VIII. And I know it's ancient. But it runs fairly well for its age.

I need some help though. I recently took it in to get some work done because I'm driving half way across the country and I needed to make sure it could make the trip.

So far, two tires have been replaced, one of the window motors has been replaced, the other window had some wiring changed, the rotors were rusted so that was fixed, the key pad lock was damaged from an accident and needed to be replaced, plus normal check up maintenance.

There's more work to be done on the vehicle. The air suspension is screwy (the car almost drags along the ground in the front), and one of the rear light covers is being replaced. Oh, and he's looking into why the car stalls when after being turned on and idling for a bit, or when making sharp turns.

I trust the guy I have doing the work, my friends have been going to him for years with their cars. But I know nothing about cars, so I'm very wary. He's given me an off the hand estimate of $1100 ... but I don't think that includes the replaced tail light cover (which he found in a salvage yard) or whatever is potential wrong that causes the vehicle to slope the way it does.

Should I continue trusting this guy, or am I crazy to let him be doing all this?

Any insight at all would be really helpful, thanks!