Originally Posted by M3PO
The difference in flow will be minimal and therefore the difference in power will be very minimal. The real choke point of the system is the cats.
I really think you would like the Dinan axleback with some test pipes. Power, little to no smell, and good, manageable sound (no drone on the freeway).
It was one of the combos I was considering but I didn't dig the look of the Dinan mufflers, and after adding up mufflers + x-pipe + tune it was getting above the budget I had allocated for this exercise. For now I'll give the Eisenmann some more time before switching to something else.
2015 M3 6MT | Yas Marina Blue, CF Roof, Cloth | Adaptive M Susp, 437M 19" Silver | Stripper
2013 X5 xDrive50i | Carbon Black | M Sport + M Perf, 333M | Loaded