[quote name='Dominik' post='39229' date='Aug 1 2007, 03:30 AM']Anybody tried the Flowmaster mufflers. Are tey any good?[/quote]
There has been quite a bit of discussion on this BB regarding exhaust systems. The 968 is very sensitive to backpressures, so installing a muffler that reduces back pressure will probably create flat spots in acceleration, and possibly a slight loss in power.
Summarizing all the discussions, there appear to be only two aftermarket exhaust systems worth considering. In the end, it seems that they are relatively close in performance and cost, but differ in "quality" of sound. The B&B exhaust system was the first of the two to hit the market. The second one is the one developed by RS Barn. The Barn system is the least expensive, and preferred by many since you have the ability to upgrade items from Barn. They have also made available a high flow cat and a performance header (both of which could be used with either system, but results are only available for the entire Barns system).
I personally have the RS Barn system on my car, and am satisfied. Both systems are noisier than the OEM unit, and sound more gutteral.