nice tip Kongmiami , but they use(d) a 2.5" coilover set …. i'm almost certain from 928Motorsports. Those are adjustable on all 4 corners.
I have those on my rally car , not allowed for the regularity one….

pic from the " 928 Expedition" site :

 

not on topic , but here is my '82 928 to replace my old friend '70 2800CS ( 3.5l M30 ) . 5 years of regularity rallies without any problems ! Just fuel,oil and tires. Due government change of rules this year , no more street legal… as it has a complete rally suspension done by Intrax Racing in the Netherlands. More, bigger Wilwood brakes, Tilton pedalbox and welded roll cage… all things now forbidden. They change rules , and we pay… as i'm building a real rally 928 , i found it most obvious to build a regularity 928 too.

But i already like the extra HP/torque in the 928 …

 

The key question do the rally rules allow you to use parts from the same model year which were specified as options?

From a look in the '82 parts catalogue PDF, Bilstein shocks were an option up to '82, option code M474. Part 928 343 055 05

Unlike Boge's, the Bilsteins actually come with threaded bodies, and a replacement Bilstein spring perch and adjuster.





A check online shows that if you order the part from Porsche, its still available from Porsche dealers, superceded by a newer part number (This is from Sunset Porsche's online catalogue):




If rules allow option parts, does this superseded part number, like the Bilsteins I bought previously for a later model, come with Bilstein-specific replacement spring perch and adjuster nut? (one of our vendors should be able to confirm, and potentially supply the part).

 

Note that Bilstein will custom valve those dampers to meed your desires on both rate and profile.

 

Yep! Last I checked it's $75+ a shock depending on if it needs parts replaced due to wear.

Another thing to note is that they will make parts for your shocks if they don't have any on the shelf. They did it for me and it wound up costing me $135 a shock for a complete rebuild.