I had adjustable GAZ shocks on my 408 and they were excellent. I bought them from ACCS.
Maybe GAZ are worth contacting for other models
e:
enquiries@gazshocks.com
t: +44 (0)1268 724585
f: +44 (0)1268 724536
Gaz Shocks Ltd
Rayridge House
Swinborne Road
Burnt Mills Industrial Estate
Basildon
Essex
SS13 1EH
UK