[ONDEMAND]

So for anyone searching "workshop-manuals dot com" has maximum torque specs per fastener size.

4 Tightening Torques > 00 Maintenance And General Data > 3 AZD M12 And M12x1.5 - Maximum Tightening Torques Ac

For the M12x1.5-10.9 that passes through the RTAB we use either 100Nm (74 ft.lbs) "ZNS - silver" or 123Nm (91 ft.lbs) for "ZN - yellow" depending on the surface coating (colour) of the fastener.

I interpret this to mean (correct me if Im wrong):

ZN = Phosphor coated | Yellow
ZNS = Cadmium plated | Silver

Description of coating | surface color from the workshop manual

"Surface color yellow (ZN): Applicable only to shank screws with
metric coarse- and fine-pitch threads according to DIN 13-28 and nuts
with nut height 0.8 x d according to DIN 934 and exclusively for a µ tot = 0.125 (screws phosphatized, nuts without subsequent treatment or galvanized. Lubrication condition: unlubricated and also oiled)"

"Surface color silver (ZNS): Applicable only to shank screws with metric coarse- and fine-pitch threads according to DIN 13-28 and nuts
with nut height 0.8 x d according to DIN 934 and exclusively for a spread of µ = 0.09 to 0.15 (screws cadmium-plated, nuts without subsequent treatment or galvanized. Lubrication condition: unlubricated and also oiled)"

Now just need to figure out which "surface color | coating" Im dealing with and apply the correct torque value. From memory I recall all fasteners in the rear axle | suspension assembly appearing silver. I always assumed all these fasteners were simply galvanized steel or alum. based on the color and texture.