I had this reply from "Buckmeister" when asking how to fit 2013 Akra to 2014 "I think there's only the one cat on 2014 models and it's part of the headers, right at the end where the can slips on. The diameter of the cat outlet is now 60mm ish not 50-51mm on models up to 2013"
Can confirm that it is in the region of 60-61mm, sometimes they're slightly oval so you get an odd reading but I believe it's supposed to be dia 60mm...