I install them for 40$. White color (6000k) to replace yellow factory ones. Will fit only vehicles that come with factory HID lamps. I have 20 watts and 40w (brighter ones, they are 130$ + installation). E90 installation is about 1 1/2 hours, X series - faster. I have sets for lci and for pre-lci.
Some other BMW stuff on my website: bmwpartsmontreal.com