That round filter is not the same as the BMW performance filter. It uses the stocknair filter or a K&N replacement (stock shape). Half of the stock US airbox is reused. This is what it looks like with no lid.
This is the half that is reused.
This is the new half.
This is the lid.
This is the new intake connector. It has wider opening to the airbox. That's why the lid is new.
