These are the Breyton E92 M3 lowering springs specifically made for this vehicle (they are not the springs that go on the 335, these will simply NOT fit the M3). Amount of lowering is 2.5cm in front and 2cm in the rear!! I’ll look into all the specs etc… and verify these ASAP.
And I do stay away from curbs, these wheels are HUGELY delicate!!!! I’ve had these types for years and spend quite a bit of $$$ fixing them.