that's true, there are no more Bilstein B6's (aka Bilstein HD) anymore in the United STates. It sucks. You could order a set of 4 off German Ebay or British Ebay for $640 USD. Not such a good deal considering the shocks used to only cost about $80 each when they sold them here...
I just went with the Bilstein Touring (B4) when I needed to replace mine. They're about as stiff (slighty less) as the sport shocks that came with the "sport package" optioned cars.