Pipes are 2-1/2" or something like that.
This muffler meets the Lime Rock Sound limit. It's also quite strong- at the Club Race last weekend a man came up and asked "is your engine turbocharged?" And I said, no, why? "Because when you lift off at the end of the main straight fire shoots out of your tailpipe like a Turbo engine. I've never seen that on a naturally aspirated engine." I explained that the, ahem, MFI speed switch was a few items down on my list. . .