I recenlty had a Dynomax Superflow (part 17740) muffler installed on my 01 Pathfinder. I have done research on the web and this muffler offers an increase in exhaust flow with limited increase in noise. The stock muffler went from 2 - 2 inch input to 1 - 2.5 inch ouput. The Dynomax has 2 - 2.25 inch input and a whopping 3 inch output. I chose to continue with the 3 inch tail pipe with no resonator.
The results is a mellow deep rumble during acceleration. While cruising on a steady speed, the exhaust is barely noticable. I had done no pre-modification quantiative measures, time acceleration, etc. However, the truck seems more responsive.
Here are a few pics?
Here you can see the monster exhaust. No fancy tip yet, so it almost appears stock. Also, notice the Air Lift bags in my coil springs. I add a few pounds of air to them when I tow my boat to level the load.
Happy Motoring
blitZ