Idk, but I like the Flowmaster 40 Delta Series or the Flowmaster 50 series, they arn't as loud as the Original 40 series, but they do sound really good on smaller V6 engines. They produce a nice deep resonating tone at idle outside of the truck, and its not too loud inside the cab. Which is a plus because sumtimes a really loud muffler will start to annoy you if youre driving down the highway for an extended amount of time. As for everyday driving they sound pretty good. If you can keep your rpm's under 3000, its sounds really good. I would recommend these to anyone who doesn't have a nice big V8 to produce that classic American Muscle sound.