So I always thought that the '91 Audi 200 Quattros all had the 20 valve head. Now I've had a couple of people tell me or act as if some '91s had 20 valve heads and some had 10 valve heads. What's the deal? -Eric Harman (ericha@wrq.com) '90 Mazda 626 Touring Sedan GT '91 Audi 200 Quattro 20v '91 Mazda Protege LX (for sale)