So far, so good! I was initially concerned about the db level that I would hear in the truck. The rpm range is limited for optimal rumble range for my Titan to be around 1500-2500. That is just what I was hoping for from my research. I really have not noticed any fuel rating increase as of yet. However, that is hard to judge due to the fact that I tend to stay in the rumble range when applicable.
WARNING: for those of you who want their tiny 2.4L engine to sound like a deep harley (myself included), you are going to need more than the muffler itself. I took out the intake resonator a couple days before I got the muffler and was impressed by the change of sound. It wasn't much but it was cool for the time being. I got the muffler in a very small amount of time and put it right on. It wasn't much louder than stock... So I cut out the exhaust resonator and wow... what a difference in sound.