I think that's broadly right Ralf, except I think it's fair to say that the springs do a bit a bit more than just keep the damper open! The spring is a temporary energy store whilst the damper is a controlling mechanism that dictates the rate at which the spring absorbs - and then releases - the dynamic inputs that are applied to it.
Suspension purists prefer to use the term 'damper' (as you have done), rather than 'shock absorber', because strictly speaking, it's the springs, the tyres and the suspension bushes that 'absorb' the shocks. (Or the occupants' backsides in the case of our Alfas!).
I think it was Rhoddy Harvey Bailey himself who wrote to the effect that the main problem with the standard 156 is that the spring is quite stiff, (which mean it takes a lot of energy to compress it, and therefore it subsequently stores a lot of energy, which at some stage has to be released again), and the dampers are too 'soft' on both 'compression' and 'rebound', so that the spring releases large amounts of energy very quickly causing the car to heave. This is particularly noticeable if another bump comes along whilst the spring is still in the process of releasing its stored energy, because the spring is trying to lengthen whilst the next road bump is trying to shorten it again. A case of the irresistable force meeting the immovable object!
From my experiences with the HB kit, there's little doubt that the valving of the revised dampers has taken firm charge of the springs, but I'm a bit puzzled by the blue springs, which seem to be even firmer than the Sportpack ones. Given that Mr HB is a race car developer though, I assume he's given priority to the race track rather than the cart track!
I'm most interested to see what Pascs thinks of his HB dampers and SP springs. This may turn out to be a good all round compromise.
Interestingly I've recently driven a New Mini Cooper, a BMW 3 Series and a new Audi A3, all of which are almost as uncomfortable as the Alfa. It seems that manufacturers, in the quest for ever improved roadholding, have completely forgotten that the prime purpose of suspension is to insulate the occupants from road irregularities. Even past masters Peugeot and Citroen are reputed now to have a firm ride. Bring back the 2CV eh?