Figured I'd pile on, just refitted my 2006 E with bi xenon projectors
Parts List
http://www.theretrofitsource.com/product_info.php?products_id=237
Bi-Xenon Morimoto Mini
-- 55w
-- 4300k
-- Gatling Gun Shroud
Post install, looks like I'll need an H4 error cancelling harness
I'd rate this medium easy.
Drop the front clip
Pull the lights
Partially dissemble the lights
Put them one at a time in the oven for 7 mins 265F
Pry them open (pull the clips up, use a chisel to work the pieces apart)
Install the projector and shroud
Fit the halves back, put in the over for 7 mins 265F
Push the clips back, let cool
Install and aim before putting the front clip back on
Front clip back on
Drive happy
My high and low beams work... but I always have the high beam indicator on. So I've ordered the extra harness to resolve that.