Just wanted to let everyone here at Stangnet what happened with my Flowmasters. Around 9 months ago my first set of flowmasters started to rattle and buzz around 900-1500 rpm. I called summit and they sent me a new set at no cost.(Had to send the others back). 6 months after that they started making the same noise again. So I called summit and explained to them the situation. So I decided to get the JBA axleback and pay the difference. So I now have the full JBA system. The sound is better with the JBAs than it was with the flows. There still is some resonance around 2500-2750 rpm, but it does sound better. I believe that there is another thread about this issue on another Mustang forum. Not sure but I think this only happening to people that have after market mid pipes and/or headers.