I'd say its as hard/easy as any other bimmer. Costs money of course. HIDs/DDE lighting for my pre-face lifted E46 goes for around ...
: $349.99(headlight housing)+$109(angel eyes)+$300(5000k HIDs) = $758.99. Compare that to dealer prices...
: . And also on Umnitza, they have an option for changing to the facelifted assemblies ~$714. I wonder why it is cheaper?
Dough