H&R has released lowering springs for the G20 3 Series. Here are the part numbers, specs and some photos.
Part No.: 28662-1
BMW 3 Series 18d/20d/20i/30i, 2WD, Type G3L (G20), without 30d 2WD,
incl. M sport suspension, not for vehicles with adaptive damping
Lowering: front / rear: 40 mm (1.57 in) (with M sport suspension: 30 mm (1.18 in))
Part no.: 28662-2
BMW 3 Series 20d xDrive + 30d 2WD, Type G3L (G20), incl. M-Sport suspension,
not for vehicles with adaptive damping
Lowering: front / rear: 40 mm (1.57 in) (with M sport suspension: 30 mm (1.18 in))
Compare to factory height before lowering:
