We installed a Agency Power stainless exhaust system on the 1999 996 C4 recently.
The car has a great tone and much better throttle response throughout the powerband. Agency power offers great fitmenthttps://ajwperformanceproductsblog.com at a price which will not break the bank either (Around 800.00 for the system). This system allows for the use of the OEM tipshttps://ajwperformanceproductsblog.com or aftermarket tips if you would like as well. AJW Performance is an Agency Power dealer.