Further to my post on CarGraphic - with which I have zero affiliation other than as a customer.
Here is my exhaust, Eisenmann 42mm exchangers, rest is CarGraphic.
They modified the Eisenmann's to fit (shortened slightly), dual 400 cell cats, exhaust path switching (normal and about 60% straight through muffler bypass) and their own in house fabricated banana muffler with GT style centre exhaust (my request).
I am programming the Motec to only actuate the bypasses when over 4000 rpm and 75% throttle. They are zero pressure valves so they are normally shut, so startup will be quiet.
They run a large factory in England that apparently does a lot of race work, so they can custom make anything.
Anyway...here are the pics
D.