I went from the stock shocks and struts on my 72 4 spd to Bilstein Sports and sometimes regret it. The car has grippy 205's on 15" wheels, and while the cornering performance is now phenomenal, a good amount of drivability and do-it-all character has been lost from the car. I have had the opportunity to drive my car back to back with another '72 with stock or similar soft dampers, and feel like unless you are stripping the car out and building a ripper, you would be better off with more forgiving damping and larger swaybars to help control body roll. I think that this setup might be as, or nearly, as fast through the corners but much easier to live with. The sports can be very harsh sometimes. Very tight and controlled feeling, but the pavement (or dirt road, in my case) really gets transmitted into the chassis and I feel like this is harder on equipment (interior rattles may appear) and passengers. I wish I had the option to adjust. The E3 saloon is such a versatile chassis, and a good bit of this is compromised with really stiff damping characteristics. Maybe I am just riding on the bump stops, but if I pulled it all apart again I might find myself just going back to stock.
In most applications, Bilstein Sports and HDs often share the same valving, but are designed for different suspension travel (or stroke). This may or may not be true for the e3/e9 chassis, since I have certainly seen the Bilsteins with a smaller diameter piston rod ( I think these are the HDs, but maybe they are the Tourings?).
I think your best bet would be some NOS or high quality used adjustable Konis or Bilstein HD's if the HDs are indeed a bit softer than the Sports. I have also seen adjustable SPAX (which are English, I have no idea if they are any good, but I have seen their advertisements throughout my vintage car mags). If you are building a ripper, get the Sports and replace driver's seat with one with better side bolstering! Post a wanted ad on here, and keep your eyes peeled on eBay for NOS. Try not to mix and match dampers front and rear. Sports might be easy to find basically brand new but previously installed, as often people swap out from the Sports right away after feeling how harsh the ride is. That's how I got mine.
