The Synchronised instruments are the same as the VI instruments - there is a certain amount of parameter editing still required to get the the Synchronised version to sound "exactly" like the VI version - but it is perfectly possible but also bear in mind that further optimisation of those samples has taken place and so there will be variation in timbre.
As an example I have to take away some of the low end 'weight' of the Synchronised Bass Drum A with an EQ to get it to closely match VI Bass Drum A .. which has a slightly less refined low end and for my purposes gets weight added to it, again with EQ.
I think VSL have been fairly clear that Silicon support for their VI libraries via Vienna Instruments Pro is not going to be soon ... if ever.
I really hope they offer those of us that have ALOT of the VI libraries bought as single instruments the opportunity to crossgrade for prices close to the way they just did with the release of Synchronised Percussion .. which is excellent .. and realistically affordable if you've already paid for the VI versions.