I did the same upgrade to my 89.5 SE (JS sent it across the pond) with the same results... Just great.
I gutted my cat and now I am failing emmisions testing with a high HC (hydrocarbon) level... Any advice would be appreciated.
went for a later spec S4 St/St sport system and EBPV spacer from SJ Sportscars in the end, couldnt be ar$ed to drive 300 miles for someone to make one for it to be the same and much more expensive and I researched a bit about turbo exhausts to find:- it aint complicated, they aint rocket science, thats what I do at work all day.
observations so far
1, its