The trade off of buying the part from Poland is that you get the part cheaper as an imported gray market part. The actual part is the exact same as if you were to buy it here but support and shipping costs money. I can't recommend one way or another where you should spend your money.
After double checking the part numbers, here is a basic description:
For the 2009 and earlier Volkswagen (red MFD screen, also covers Tiguan and 2008 Passat):
1Z0 035 729 B (1Z0035729B)
For the 2010 and newer (and 2009 Passat, and all cars with white MFD screen)
1Z0 035 729 A (1Z0035729A), 1Z0 035 729 D (1Z0035729D), or 1Z0 035 729 C (1Z0035729C). The difference is production, A was for early white MFD cars until production date 5/25/2009, D is newer prod date 5/25/2009-6/22/2009, and C appears to be the newest for car prod date 6/22/2009-present. There is also 1Z0 035 729 e but my parts catalog doesn't go that new yet so I don't know more details on it.
The phone function should all work the same and there's probably some parts mixing on the assembly line anyways. The Ebay auction also includes the bluetooth antenna. 9w2 has an integrated antenna, 9w3 requires an external antenna, VW#8P0 035 503 . The link also says it includes a microphone. I'm not sure if it's needed because others haven't mentioned installing it and this may have been why the early guesses on retrofitting 9w3 were that it needed a new wire harness.