I finally picked her up this evening.
I'll give a quick summary with more to follow this weekend including before and after pics (it's too dark out right now).
Bottom line up front: With only 5 or so miles so far I love the Bilstein B12 Prokit.
FYI, I have a 2009 non-sport package 128i with stock wheels and 205/50/17 michelin aspin performance winter/snow tires. The tires are surprisingly grippy for a winter tire. Also, this B12 Prokit is officially made for the euro-spec 125i, but as far as I know the only difference between the 125i and the US spec 128i is the engine.
The drop is perfect for me, not too slammed with a nice 1 - 1 1/2 finger gap front and rear.
The Eibach Prokit springs, like those I had on my '97 Prelude Type SH and my '06 Civic Si, seem perfectly suited for a DD with the first inch or so of travel being fairly soft. Good for ride quality.
I haven't had a chance to push the car too much yet, but it certainly feels tighter and I can also feel the lower center of gravity.
I can't wait for spring so I can install some 18" rubber, probably 225/40/18's all around to avoid any understeer caused by putting 245/255's in the back.
For my fellow service men in Germany, the shop I mentioned in my earlier post gave me three hours(out of the six hours it took them) of labor discount, or 150 euro. So the total installed for someone else would be 910 euro or so. Still a great deal if you ask me. At current rates that's still out the door for around $1150.
Like I said, more to come this weekend, but I absolutely would recommend this setup. I hope someone in the states can figure out how to get it there.