I just did the the 4.5.0.81 upgrade on my 8310 using Desktop Manager 4.6 and the Vodaphone Australia 4.5.0.81 package.
No problemos, took maybe 30 minutes and it worked like a charm. Almost everything was just the way it was with my themes and applications.
After that I helped a friend upgrade her 8320. Again it worked like a charm.
No issues with 4.5.0.81 to report as of yet.