Ya aint gotta timing chain on that car.. its a $15 belt. If you're so inclined, you could change the belt yourself in your driveway in an afternoon. It doesnt take much in the area of tools, and you can mess it up as much as you want and it wont hurt the car. If you do decide to do it yourself, pick up the haynes manual too- it'll take you through the whole process, and you'll save at least 200 bucks. The rattling that you hear when you rev the engine is more than likely the heat shielding on the exhaust manifold. There are two pieces.. one that bolts directly onto the manifold that you can get to from under the hood (4 bolts, 12 or 13mm, check and see if they're tight. While you're at it, rip off that silver pipe that goes from there to your air box- its bad news, don't ask, just do ;) )if thats not where the rattle is from, you might wanna run the car by a muffler shop, they'll be able to fix you up in no time. The sputtering you're hearing might be the car backfiring, and since you're hearing it inside the car, you probably have an exhaust leak somewhere. you can get that fixed when you run the car by the above mentioned muffler shop :).

50k, eh? thats pretty nice.. my '87 740 had 62k on it when i got it 4 years ago. And you're right.. the miles aren't an indication of how good a condition the car is in (ask me how i know..) At least yours is a manual, you shouldn't run into any transmission problems.

Did the car sit up for a while?

Good luck!