I just happened to get two flowmaster 40 series for a really good price and im thinking about removing my factory muffler and just bolting one of the 40 series up just to see how it sounds. ill try and get a decent video up id like to do true duel exhaust but if just one doesn't sound good that ill just put them on my truck. Right now i just have a muffler delete. I didnt know that it was cut off till i did a clutch job but honestly it sounds great.

 

 

That last one could use a couple resonators too, a little raspy when revved.

I have a Megan catback which is a decent exhaust but has a little too much of the VQ35 trumpet sound. Swapped the rear muffler with a Vibrant Stealth muffler. Sounds a lot better and quieter at freeway speeds. Probably end up swapping the resonator with the Vibrant Ultra Quiet one at some point.

Flowmasters seem to be more mellow on V6 and I4 engines than V8s so they sound pretty good assuming you also have a resonator(s)