Do you know exactly what these “specially valved Bilstein shocks” are? How are they different from stock e9s?
Really best to talk to H&B the about the specific variations. They are revalved. They are shorter stroke acknowledging shorter springs. Similar to what Bilatein sports did a while ago I believe. The rears are modified 2002 shocks. Again talk to them about the application. They are very accessible.
Remember H&B were the US Alpina guys in N America in the 1970s. Owned Road and Track for aftermarket BMW press in the day. Recommend you look at articles from the period. I don’t know of anybody who has more true period BMW aftermarket knowledge.
Love the setup. Compliant and balanced.