The screw is standard right hand thread (i.e.: turn counter-clockwise to remove). Those bloody things always fawk up. If you can't get it out with a screw extractor then just break the old rotor off and pull the screw with vise-grips. Put a little anti-seize on the new screw before you put it in. Check e-gay for cats.
How long has the car been sitting? It could be bad gas. While you're doing the tune up you might as well put in new spark plugs, ign. wires and fuel filter too.

 

Thanx 93TurboD for the quick reply. I'll have to try that. The car hasn't been sitting, I've been driving it. I noticed the back pressure feeling and smell this morning while driving to work. I hope you meant ebay and not egay for cats. I checked there and someone is selling one for like 65 bucks including shipping. Have you ever heard of or used OBX racing parts?

 

I've heard of (never used) OBX. Word on the street is you get what you pay for. They have a reputation of building crappy parts, whether or not this has changed I don't know. Stock will do you just fine, unless you've turbocharged your car, then I'd get a high flow. Any muffler shop in your area should have a cat to fit your car if you don't want to pay dealer prices. And warranty issues will be easier to deal with if you buy locally.
BTW: e-bay = e-gay (It's a joke) :chuckles:

 

I called the local midas shop and they can to put one on for 210.00 including labor, so I think I'll go that route.