Originally Posted by MrFatbooty
The stock cat doesn't really become much of a flow restriction unless you go to 2.5" piping or it gets really old. Since you have done neither you might as well just keep the stock cat.
Still, on a '98 with that kind of mileage and 2.25" exhaust piping the stock cat is not a problem.
I have to completely disagree with you on this. The stock cat is terribly restrictive and is one of the worst "bottlenecks" in the entire exhaust system. If given the choice, I would even opt to run the stock exhaust manifold with a high-flow Carsound over running an upgraded header mated with the stock cat. In the case of a a DC or Comptech "USDM-style" header (both with 2.00" OD collectors), I would suggest a 2.25" Carsound. My shop of choice for Carsounds is SMS Products (SMSProducts@adelphia.net - 540-287-6385). Dave (the owner) will be able to provide you with a complete bolt-on cat for your application.