2- Bore size (mk2 16v/mk3 20vt same bore 55.5mm) whereas as your 1.8 is 50mm iirc so will need a adapter to fit
Just gonna mention that on msn to you, before you went
![Doh :doh: :doh:](/forums/styles/seatcupra/oldforumsmileys/doh.gif)
The pipe on the cat (going to the centre section) is going to be the standard bore, as flaper mentioned!!!