Yea Kai, that's the way it works. I'm not a hippie (heh) but I think you should get a high-flow catalytic convertor like a Carsound or Catco just so you don't have to get back under to change your cat for inspection. Carsound has been shown to be the best flowing cat.

Also the size of the cat will depend on the diameter of the piping on your header and your exhaust, remember that. You always want to get bigger as you go out, you dont want to create bottlenecks.