I have a dilemma and I am pulling my hair out over a 3" vs 2.5" exhaust for my 260z. I have a N/A L28 3.2L stroker, 11:1 compression, headwork and port matching, an MSA 3-2 header, weber 45s. I use the car on the track and street. This motor is still being broken in so I don't know what it will make yet on the dyno. I had a 3" nice exhaust made up and is currently on the car, but it is straight piped and insanely loud. I have two paths I can take; pick up a magnaflow 14867 (or maybe an oval type instead?) muffler and 18" vibrant 4" body resonator for the 3" system and keep it, or scrap it and have a 2.5" system made. The 3" vs 2.5" debate is mostly out of fear I went too large on the exhaust. I want to make sure I get it right. Can anyone help me put my mind to rest so I can stop obsessively searching online through countless forums?