I have a 2008 S3 with standard 18" wheels. I'm buying a pair of Porsche cayenne (18z) callipers this week. Also a set of ml450 discs (350mm). I've been trying to find out for ages if this is a straight bolt on kit ?? Do I need spacers to clear the inside face of the wheel? I hear this is a common conversion but not got a message back from any one who has done it to find out what they did. Any help will be great. I've messaged N8 but not had anything back yet.