I have have a carven 3" X-pipe mid muffler delete with 3" pipe into Carven R series 3" mufflers right about 6" before 5" carven tips on my widebody scat pack charger. I also have my active exhaust valves permanently open.
The tone is super deep and smooth and and has almost no pop or crackle. It also allows enough back pressure to keep low end torque to spin the 315mm tires at 45mph.