Since I'm on a lunch break, I'll give the short end of this but expand a bit later.
First, it's a bit more difficult than it seems. Yes, everything fits - but some of the wiring can get tricky. I wasn't around for too much of the wiring so I'm not 100% sure on what goes and what stays. My advice is get a good wiring schematic for both vehicles and then compare the harness. I can tell you this - the EEC harness does need to change. Obviously, you will need the Super Coupe's EEC since you'll have alot more for the computer to watch. There are some harnesses that had all the right wires, just needed to be re-pinned.
If I remember right, everything else works just fine with very little or no modification. I didn't change any the suspension on my 91. I did however take the SC drivetrain (rear end, halfshalfts, driveshaft, etc) You'll also need to change the fuel pump in the N/A 'Bird and might as well just upgrade to a 255lph unit. I didn't take the auto ride control or the ABS from the donor car - the auto ride didn't mean that much to me, and for the brakes - why fix what isn't broke? I've gotten along just fine without the ABS so why change it. I also didn't swap the dashes - some say you do, others say you don't.
Handling: I've driven both an SC and an LX and IMO, there doesn't seem to be much of a difference between the two - atleast that I can tell. Since you'll have the motor out, you could take the sway bars from the SC.
OK, this was a bit more than I anticipated on typing, but it gives you a good start on what's going on. If you want, feel free to e-mail me (MelonSC@gmail.com) with any other questions, or post here and I'll do my best to answer them. Hopefully the few others that had a good hand in the project can chime in some other thoughts I may have missed as well.
-Melon