Just had a Flowmaster 50 series welded on behind the 3 cats my 4.0 sohc to replace the stocker that had 153,000 miles on it. Mine was a single offset in/single center out, and couldn't be happier with the sound. Very-very quiet at idle, very mellow tone under acceleration, depending on how heavy your foot is, even under heavy acceleration sounds great, not too loud. I was afraid there would be the "drone" at hwy speed but was very happy when it was very minimal.