Pretty sure your rear OE shocks are Bilstein (mine are). Not likely the B6 model but something very close.
Bilstein make a B4 version (coincidentally, the B4 is black and not yellow). I have recently fitted B4 front shocks and will fit the B4 rears sometime soon. Very happy with the ride quality.
https://www.bilstein-shocks.co.uk/bl...nd-bilstein-b6