Im not sure, i forget which kind but some are better than others for turbo application. It totally depends on the shop you go to as well. You should ask around and see what people have used on their setups, im sure some people with saabs have used various kinds of mufflers. I do know SaabSavior uses MagnaFlow. Im sure anything would work well, just find people who have them.
2000 Saab 9-3 Viggen Sedan
-BSR Cat-Back and Intake