So it appears that the listing Bilstein has for the U.S. Smarts (451) is incorrect.
Upon ordering them, it was a "confirmed fitment" for 451s. But after receiving them and sizing them up for a customer's Smart, we confirmed that it's only for the 450 chassis.
Therefore we have a brand new set of Bilstein B14 PSS coilovers (HE5-A763) we need to sell to a Euro Smart enthusiast. Tell your 450 friends!
They are listed in our CLASSIFIEDS but we will sell them for $799 if you mention SCOA. Just call 415.226.2500