Review on Flowmaster 817511 Axle Back System 409S by Demetrius Young

Very good deep sound. Not too loud in my opinion. Gives the Mustang a nice aggressive sound that matches the look. The hardest part of the installation was removing the stock exhaust pipes/mufflers. It took some penetrating oil and strength to remove the original clamps and separate the rusted sections of pipe. If you're using the socket by hand, do yourself a favor and use a long tube over the socket for much more leverage. With the OEM mufflers removed, the Flowmasters fitted perfectly, the mounting brackets were in the correct position and the exhaust pipes were right in the middle of the bumper cutouts. Great sound, easy installation and I will definitely buy these Flowmasters again.