Straight pipe from the end of the exhaust manifold, straight pipe from the resonator, what? Just so you know, if it's the former, your car will be ear piercing loud as hell at WOT. I am working on a design for a 6 in 1 exhaust manifold without CAT's, then a single race CAT to a 3" single pipe with two (one mid, one end) race mufflers with a optional take off at the first muffler. This setup will be on the margins of 100 DB limits for my events with the take off. Without either muffler, I'm certain it would be way over.
2011 BMW M3 ZCP in Melbourne Red, Apex wheels (ARC-8 and EC-7's) with Bridgestone RE-71R's.