If you don't want to spend a boat load for new shocks, you can try to find some 03/04 Cobra Bilsteins. You can usually find people selling them. They are a great upgrade. I also went with H&R for springs. I went with the Race Springs instead of the SS.
Do the IRS shocks work for a straight axle setup? I thought the IRS used struts, not shocks.
I'm all for Bilsteins, but I'd double check that the Cobra units interchange.
For the OP:
Start with full-length subframe connectors. Depending on how much the springs you got dropped the car, get shocks to match; stock shocks will reasonably handle a 1" drop, but much more than that and you're putting your shocks on borrowed time.
I suggest against a strut-tower brace unless you have oversteer problems, and anyone that suggests a rear shock tower brace doesn't know what they're talking about.
One thing you could do is go to Maximum Motorsports, and get their most basic grip package. It comes with springs, shocks/struts, swaybars, and some bushings. As it sounds like you already have springs, you can talk to them, and they'll take the springs out and credit the difference, or might even let you swap springs for SFCs. They'll also know the right shocks to match the springs you already have.
Good luck with it!