Alright at the moment i have flowmaster 40s and custom 3 inch piping and im thinking about switchin to the slp loudmouth full cat back. What would be the difference if i did change and should i jst keep my same setup.

 

From what I've been told you would need to switch from an H to X pipe, as an H-pipe is better for a chambered muffler like the flows, and an X is better for straight through mufflers like the loudmouth