Common problem with these cars is headgasket failure, but the newer gaskets out now have pretty much eliminated that problem, when you rebuild use a quality gasket set, fel-pro or corteco(what gm is using now on many cars) I also hear good things about, just dont use an oem one from 92-93 thats been sitting around, youll have the same problem possibly, be sure the head and block surfaces are clean and not warped.
Quad 4's can be alot of fun to play with, even the lower output version makes great torque for a 4 cyl motor(go ahead compare it to higher hp honda vtec motors etc), many of the parts are interchangable and arent too exspensive(compared to other vehicles nowadays). Most mechanics dont like to work on these motors and charge alot sometimes when they do, truth is its not all that hard to do yourself get a manual, plan to spend some money on tools you may not have, research on the internet and in the manual, double check things, work safely. Quad 4's are easiest to work on out of the car, the timing chain housing is a real pain with the motor still in the car, but it can be done that way.
Since the car has been sitting you would want to look over it as much as possible, depending on your area look the car over for rust before going any further than that, a rusted out rear shock tower is a pain to replace, the quad has no plug wires to replace but looking over the coil pack couldnt hurt-look for arcing, this looks like someone drew on it with a pencil sorta, change oil and filter, plugs, fuel filter(get as much old gas out, siphon or whatever and buy a fresh can of gas to put in), I would probably replace the brake parts if rust is forming-have rotors turned, the coolant should be done when you do the head gasket anyway, trans fluid could be replaced, if its a 5 speed get 2 (yellow)bottles of Penzoil "syncromesh" fluid from Auto zone its made for these types of transmissions and isnt a fortune like the dealer fluid, if its not a 5 speed then drop the pan and change the filter and fluid. Check over the chassis as much as possible, for safety reasons.
Go here for more info on the quad 4, lotsa info to be had there:
http://www.quad4forums.com/forums/