Thinking of installing a Dynomax Ultra flow on my 01' Sup Crew w/ 5.4L. On there site they have some sound clips of a 5.4L Exp. that sounds really good. Any of ya'll ever tried these before ?

 

I've used them on several vehicles. The Ultra-Flows are excellent. Their other mufflers have low flow rates. The Ultra-Flows have a very throaty sound; it's wonderful. The Ultra-Flows have extremely high flow rates, but I'm sure that you saw those numbers on their website in the sizing/diagram area. VERY IMPORTANT = don't use any muffler that they make that is not stainless steel construction. Their aluminized steel muffler's internal baffles will rot out in 2 years with the outside looking perfect; next thing that you know, fiberglass is blowing out of your tailpipe.