on the bottom of the housing, mine has 3 posts that are the mounting posts for the OEM ballast. also, there is an oval shaped divet that can be punched out to allow the connnection for the ballast to be connected to the wiring harness inside the housing.
i have not see if the d2s ignitors will mount to the projector bowl yet. but it is easily an H7 bulb. i have d2s bulbs and ignitors in the garage from an old set of machs. ill see if they mount up. ill update ya when i do.