I have an 04 330Xi and I went with the H&R springs and Bilstein combo..... Works great!! See attached pics. Sorry about the dark ones, taken with my Blackberry with very poor lighting... Pics of front and rear installations.
The pic with the stock rim is the the rear whell after the install (before installing my summers) and the pic with the M6 rim is from last summer before the upgrade. Much better look and handling!!
Painted the calipers and installed SS Brake lines @ same time.
Love it! Car handled great before; even better now... Went with the Sport package (not tracking the car; and daily driver)......