UPDATE BELLOWS. First let me say that Flowmaster makes a great product and what they describe is usually true. So when they say that this muffler absorbs resonance and eliminates noise in the cabin, they are NOT kidding! I installed it on a 2002 2500hd Silverado with extended 6.0 liter Vortec cab. I drove it without a muffler for about a year. It's been chilly for a while. Rumbled through the city and all the cattle. But I was fed up and after my last trip I'm done with it. Was shopping and decided on this silencer. My intuition told me I should buy a dual-inlet, dual-exit Super 44, but I didn't want to risk the freeway rumble. After installing it with exhaust pipes all the way back, I decided to take the interstate for a ride. I was shocked! Almost normal sound to my ears. It was much more comfortable to drive in, but I was disappointed that I barely heard my pickup. Conclusion: If you are bored with a drone and you have a 6.0 Vortec, this is for you! If you're a young guy like me, this won't suit your muscle car side. If the sound changes after a while I'll edit this review to see if I like it more or less. UPDATE 04/26/2017 Just driven 900 miles with new exhaust and WOW! I am very satisfied with the handling of my truck. Even when I shift into low gear, it's just a pleasant hum. I'll say there's a slight rumble at low rpm, but I don't consider it an uncomfortable noise. I am very satisfied with this damper and can only recommend it.