I went with Eibach Pro Kit. It's mild. I wish I matched with shocks though as vertical control is not as good (a bit of pogo effect when the car crests over hills). Feels great on the track though.
F25 X3 N20:
2010 B8 A4 2.0T quattro (current)/
2013 F25 X3 x28 N20 (babymobile)