Rizzo
Enthusiast
Here are a couple vids of the 98 GTS with no cats, Borla, smooth tubes and K/N filters. It has nice rumble. It's a lot louder driving around but not obnoxious. If you step on it, it gets pretty loud. In 6th on the highway you can barely tell you have aftermarket exhaust.
http://www.youtube.com/watch?v=OjyK0hcImME
http://www.youtube.com/watch?v=l_Vx7unAFOM

http://www.youtube.com/watch?v=OjyK0hcImME
http://www.youtube.com/watch?v=l_Vx7unAFOM