Diameter of Genuine center section?

[Diagro]

Hey

anyone know what size the genuine center section is on a clio 172?

I have a ph1 172 genuine exhaust on my car and am looking to stick a stainless backbox on from someone on Facebook.
He found the internal diameter of the backbox pipe was 58 mm

ta

 

[Diagro]

Anyone got any ideas?

 

[George182]

I 'think' that the 172/182 exhausts as are 2.25"...

 

[Diagro]

Damn of they are 2.25" then this 2.5" wont fit... Hmm