Spoke to Heasmans, very helpful dudes
It seems that there are "genuine" Bilsteins for the Stagea, that Bilstein put in their catalog
ie
Front B46-2590
Rear B46-2589
but these are harder to get, and are a bit softer
the others that fit, are bit firmer and easily in stock are
R33 GTR front (B46-2107)
GTST Rears (B46-1916)
Hope this helps people
PS I spoke to Travers Wood at Bilstein Racing, free plug, good guy