After some digging, I've been able to confirm that Group 7 filters are made by ArvinMeritor, the parent company of Purolator. It also seems clear that they are indeed sold mainly to garages and oil change houses as others have stated. Neither the ArvinMeritor nor the Purolator site have any mention of Group 7 filters. It would be very interesting to see one cut open and to get some efficiency/flow specs.