Gauge size is 52mm hence the ring around the outside. I had my shop install it for me they made up the custom ring around it. The AFG gets hooked to a separate wide band o2 sensor in my DP. I had to have an extra bung welded on to it for this to work.
Rob
Spoke to your installer and he says he will need your car there to get measurements off yours. He says your car will be there for other installs in the next few days and he will get measurements then... He may make more than one if there is sufficient intrest from other MZ6/MS6 owners....