So it fitted the standard backbox that I bought on FPS. it's decent enough and seemed to fit ok on to the middle pipe. Ten minutes after driving, bleedin blowing from the join grrr. I used the existing gasket and applied some paste to get a seal but I think I need new bolts as the old ones I reused but they were a pain to get off and they were badly rusted. The faces on the two pipes are flush so do you have any tips when I come to look at it again. i dont have issue with the exhaust, it looks a decent item.
Get a new gasket or even 2 if theres a gap and a pair of stainless bolts, they should just do up together nicely
Just to add, sorted today with two new bolts and a good smear of assembly paste.