Awhile back when the report came out about flow rates of the popular mufflers, I read responses from the Flowmaster reps...."Ah, forget those tests....engines flow differently than the testing methods did."
I have the Welded Ultra Flo mufflers on my Charger. I had Flowmasters before. I did like the WOT sound of the Flowmasters but grew tired of the sound at all other times.