Sure, jump right in. Destroy an expensive set of cats before you really know if it is actually the problem.
You havn't described enough for me to go after the cats.
Have you driven the car with a fuel pressure gauge hooked up? From what little you have described, you could have a fuel supply problem.
So go ahead. And if that doesn't work, try a new set of plugs, then wires, then whatever comes to mind. By the time your done it may still run bad and you have spent enough that your could have bought another car.
Look into fuel supply problems. Your problem sounds similar to many other late 99 and 00 Contours with returnless fuel system and a plugged fuel pump intake screen.
Have fun!
