This thing has been knocking around in my head and i am very grateful to Russj, Legin for answering my messages and to frogfoot for giving a different perspective. It was very helpful and i think i understand the issue a bit better thanks to all of you.
The sport suspension is lower by 10-11 mm in the front only compared to the standard 350. The springs are shorter at the front, has block spacers at the back springs and the dampers are different.
The Eibachs lower the whole car by 25 mm as per their literature. If you look at the Bilsteins - 25 mm lowering is suitable for B6s and B8s are recommended for lowering 30-40 mm or above. The B8s are B6s with a shortened stroke.
So In my mind, if i were to hypothetically put on B6s all around, i could decide on Eibachs later on with the same dampers. Correct? I think so as 25 mm will still be within the tolerances of B6.
I am slightly hesitant to lower, as i believe that ride height on Yorkshire roads is a bit of an issue already. So i am veering the direction of B6 dampers all around.
Now, Legin has noted above that the B8s with AMG springs, the front rides slightly higher than the back. Would that be the case with B6s and stock sport springs? That would be a pain - as i can live with the "arse in the air" but not the "boat" look.
Suggestions, opinions, criticisms please?