Starting this thread since I've made the purchase for this exhaust. I confirmed with the company that all piping is at least 2.5" internal diameter with a much larger collection pipe. I'll take measurements of my own for confirmation, but will share video clips with the forum.
The ULTIMATE E46 M3 Sound Compilation (youtube.com)
David
The ULTIMATE E46 M3 Sound Compilation (youtube.com)
David
Comment