Yes it propably would pass an mot no problem at all with a high flow cat but the MOT is not the be all and end all to whats law on the road. As i keep saying on the mk5 forum theres a slight issue with VOSA if your stopped for a random check and they want to get picky as it does not have a catalyst converter that was type approved with the car anymore this is a little know about law that was brought in for models after a certain time 2001 iirc (I could be way out on the date) even alot of dealers don't know about it or parts companies.