i'm not sure about yours but the '04 and '05 titans have a 2.5" offset inlet (towards outside of truck) and center 2.5" outlet. The stock muffler is huge!! so you're probably going to have to add more pipe to either the front or the back of the exhaust
my 04 titan has 3" exhaust on it with the stock exhaust and I put an original 40 flowmaster on it with a 3 1/2" tip going out at a 45 behind the tire and it sounds really good. I want the banks exhaust but can't afford it right now. Mine doesn't crackle at all but is louder at lower rpm's. It also helped my mileage a little bit. 2004 galaxy black 4x4 non bt air box mod and coming soon 2* timing advance. 85000 miles and going strong
I just had the flowmaster 40 put on and kept stock pipes. Its sounds nice enough, drone is bad at around 30mph and 40mph in the cabin, but its only been about week, so I'll let you know if it settles down.