welcome to max man, 4 doors ftw
what kind of idle problems? almost alll e30s have whacky idle problems at some point in their lives with some variations of symptoms. Anything from Vaccum leaks, bad MAFs, and/or idle valves (my scenario with my old m20) , or even crank/o2 sensors, check the plugs and wires too, or even the distributor.. as they have all been some of many culprits of idle problems with some e30s.
looks like a good bang for your buck, congrats, i will see you around once mine's back on the road