You will have the bump stop issue no matter what system you use that retains the stock edc shocks. There isn't much point IMO to getting an adjustable sleeve-over kit if you only plan to lower 10 mm. If you want the most mild drop, dinan is your answer. Dinan is however over priced. I would recommend eibach springs with e36 bump stops. I previously ran eibachs with OEM bump stops and did not notice any issues with them. Ride quality was good and height was conservative.
'04 E46 M3 - Jet Black - Sold
'08 E90 M3 - Alpine White - Sold
'13 E92 M3 - Silverstone II - Sold
'13 E92 M3 - Alpine White - Ohlins TTX, Fall-Line Suspension Arms/Bushings, AP Racing BBK, OE GTS Aero, Cobra Seats, Akrapovic GT4, GMG 4-point, BBS E88