For bang for the buck, exhaust and 5% or 10% pulley will be something you will feel right away. Just make sure that you do the exhaust first. I would also get a larger MAF and CAI. The stock maf is 55 mm and the stock TB is 60 mm.
If you do the resonator only and find the exhaust too loud you can always add mufflers to the rear. The resonator is the single largest restriction in the stock exhaust system. For those mods the deletion of the factory resonator and mufflers are more than enough to relieve some back pressure.
On my 90 SC I have a SCP CAI, C&L 73mm MAF, Racer Walsh 10%+ pulley, Custom Stainless Y-Pipe and 2 Magnaflow SS Mufflers and I get a solid 15lbs. of boost. The exhaust tone sounds more like an F1 race car when in the gas but is very mellow at idle and cruising speeds. It sounds almost like a V-8 when it is idling, NO JOKE! Everyone that hears it really likes the way that it sounds. No obnoxious droan. I highly reccomend Magnaflow or Borla over anything else for that reason. I have experience with both on my cars.
I have a 95 SC 5-speed that I am getting ready to mod for summer in the next month and I am going to do just about the same thing to it except I am going to add a 70mm TB to it that I bought last year and only a 5% pulley -vs- the 10%.
Hope this helps.
Bob