Just be really careful when lowering...we have a 2002 3325XI and right after we lowered it (max for the all wheel drive is 1.5 inch in the front and 1 inch in the back eh) out Right Stabilizer link broke after about a week of driving..bought a new link form BMW ($100) and then 2 days after it broke again...went to the dealer we bought the car from and nobody (idiots if u ask me!) could figure out why the link broke...they suggested we put in both new front links (another $250)....then the NEXT day it broke again....on the same right side....Finally we took the car to a good European shop in and after me educating myself some more....we now realized ($400 later) that because the care is lowered the original stabilizer link was actually now too long....so this guy suggested to install 325i links instead because the 325i actually sits lower than the 325xi...and low and behold....i've been driving the car for a few days and NO problems so far!
Those links can't be messed with----because if it brakes and you leave it in, it can get caught in the brake line and could snap ur brake line while driving. If it brakes...you would here a small tok-tok-tok as you turn corners.
So point of my story---- you have to change your stabilizer links along with lowering the car...I suggest you take it to a shop that only specializes in European cars.
And try to use only Eibach springs..they're supposedly one of the best.
Hope my info helps