"What Will I get if I Upgrade my Microsoft Silver Account to Gold?
Great news! Microsoft and Wargaming have teamed up to bring you this exclusive offer when you upgrade your Silver Xbox Live Trial Account to a Gold Xbox Live Account.
Currently, World of Tanks is only available for Gold Xbox Live Members. However, we are now offering players a Free 7-day trial Silver Membership, that will allow them acess to World of Tanks. Once your 7-day Trial has expired you will no longer have access
to World of Tanks.
Microsoft is offering all players who upgrade from the 7 day Free Silver Trial to an Gold Xbox Live membership, access to the rare Tier III Pz.Kpfw. II Ausf. J German Premium Light Tank, which is currently not available anywhere else in game."