If you are keeping the OEM shocks, just do springs. I doubt that you'll be riding on the bump stops if you lower the car 10mm. If you are worried suspension travel, get the Dinan Stage I which provides new front and rear mounts which help gain a small increase in travel.
Sleeve over kits are a waste. The WHOLE point of a height adjustable system is to either corner balance the car or to slam the car as low as possible. Your car is stock and it comes optimally balanced, you don't want to slam the car...so what's the point?
I have the Dinan Stage II plus camber plates on a non-EDC suspension. It looks much better and turns in much nicer than OEM. Unless I'm on the track, I can't detect much of a difference in performance.
2013 F30 328i Melbourne Red
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red