I have almost the same start as you do... I'm going to have to go with Steve on this one, definately most cheap bang for the buck is going to be underdrive pulleys... just be careful if you have a '94 and make sure that they include the spacer. Otherwise, if you have a late model, the supercharger top is easy to remove, you can buy a 3/4" inch spacer for $90 or $95 that should be good for a few HP. Unfortunately there really aren't too many CHEAP mods to be done... maybe Iridium plugs if you can replace them yourself, also MAF and Throttle body are pretty easy to replace, but I don't know that they'll give you a great deal of extra oomph. Flywheel is a good upgrade, but VERY expensive in both parts and labor. I think the standard starter mods are:
1. Exhaust ($400 give or take)
2. 5% or 10% pulley ($65-$75)
Intake (I paid $180 for custom ram-air mandrel bent 3" and K&N cone)
Underdrive pulleys ($160 for ASP steel, $260(?) for March Aluminum (which I'd buy if I were to do it again)
Raised top ($250????) or 3/4" spacer ($90-$100)
double intercooler ($60-$100 for 2nd core, plus labor $200-$450)
plenum (??? don't know, check out magnum powers)
throttle body ($250????)
MAF ($160-$200)
New plugs are always good for a few HP over old plugs, but they are a royal pain to replace (NGK Iridium $7.99 each) as well as wires (magnacor $75-$90)
Porting is great if you can do it yourself, not sure what you'll see in the way of gain though and it does involve taking things apart...