You aren't in any forum violation, this is a good thread aimed at better educating.
From what I have read, done and personally seen, it appears that the standard Magnaflow high flow universals in the correct pipe sizing work fine for the Pre2000 cars. The 2000 and up cars though appear to have a much more sensative setting for the emission reduction that occurs in the cat.
In your case, I would hit up ebay/amazon for the best priced high flow universal in the correct sized pipe. I believe your piping should be 2.5", but it'* always better to measure and be safe.
00 Regal GS: All kinds of cool stuff.