OK, this may seem weird. I brought a catalic converter from GSF for my Audi 80 2ltr 16v but the olive/silencing ring from my car does not fit the new cat, i cannot find an olive/silencing ring any where that is 6.5 cm across. The one i have from my car is 6 3/4. Audi themselves say they would only sell me what i already have. GSF say go to AUDI. My mates cant find a thing either from where thay work. Has anyone else had this problem. The downpipe is an original Audi part. NEW CAT OLD CAT So weird.