went to
http://www.dietersmotorsports.com/twinpipe911.htm
911 twin pipe muffler conversion.
On my 79 911sc i have been discussing with a mechanic to do this. his belief is that with allowing more flow there will be a noticeable difference in performance.
He said if I removed the catalytic converter for a test pipe, my low end torque will suffer, so i will have to turn up the idle which was not recommended.
What is everyones thoughts and experiences with this. Any performance upgrade with following Dieters recommendation.