Spirax 80W90, now synthetic?

["Reid, Warren" <Warren.Reid@xxxxxxxxxxxxxxxxxxx>]

With all this talk about smoother shifting in 105 gearboxes with Spirax gear oil, I decided to try and track some down to put in the Spider and GTV. However on enquiring with the Shell technical people (here in Australia) I was told that the old Spirax HD 80W90 had been superseded by Spirax A 80W90 (semi synthetic) and Spirax AX 80W90 (fully synthetic). I have a synthetic (Amsoil) currently in my Spider gearbox and suspect that the synchros don't quite like this as well as the previous non synthetic that was in there. I've noticed other comments about the synthetics not allowing the synchros to work as well also.
 
Can anyone comment on this and whether the current range of Spirax products is the same the world over (and still the best for 105 gearboxes)?
 
Warren Reid
Melbourne Australia
86 Spider Veloce
68 1750 GTV
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided