They're made by Hella, I ordered them online. I can't remember who I got them from though... I think they were around $70.
When you get them they're red, I took them apart and sanded/painted them. When I sold the RS
I took them off and put them on my WRX Sedan (currently for sale as I now have a wagon...) I will probably take them off the sedan and put them on the wagon.
If you get them let me know and I'll dig up the step by step instructions on how to install them on an Impreza. It's not super dificult (sp?), just kind of a pain.