A light engine housing comprising a mixing chamber element, a driver chamber element and/or a connection element, one or more of which is removable. A light engine comprising (1) a light engine housing and (2) a mixing chamber module and/or a driver module removably attached to and/or positioned in the light engine housing. Also, a light engine comprising (1) a light engine housing and a mixing chamber module and/or a driver module. Also, a solid state light engine comprising a light engine housing comprising at least a first connection element.