Look into the Eibach Pro Kit lowering springs. I had them on my 330i, one of the best mods ever. Total drop was like 0.75 inches in the back and 1.50 inches in the front. But I previously had sport suspension, so I'm not sure if the drop will be the same.
The ride looked and felt great after. I ran in through winter at that height and I never got stuck, I actually drove in some pretty terrible conditions with no problem.
I also think the springs are designed to be compatible with the stock shocks.
I'm in Australia currently and don't have pics of my old ride, but there could be pics of my old 330i lying around the forum somewhere.
'94 318i Sedan R.I.P.
'98 Honda Accord V6 SOLD
'95 325i Cabriolet R.I.P. (thanks sis)
'93 Honda Del Sol SOLD
'94 JDM Integra GSR SOLD
'01 330i SOLD
'01 M3 Cabriolet