When I replaced the na engine in my 1980 Audi 5000 with a 5 cylinder turbo, I never changed out the original 200mm clutch with a 228mm. Is there some reason a 228mm clutch and preassure plate for a gas 5 cylinder wouldn't work if it has the same ID and the same number of teeth?
I'm sorry I don't have an answer to your question, but can you tell us more about your project? I have a TD engine I'd like to put in a Quattro some day, and I'm sure I'll have lots of similar questions about clutches, etc.