I have seen multiple cars with the +50mm offset.
the Volk site says the 17x8.5 +50mm will clear for the MY04 5x100. I guess this could mean that +50mm offset 5x114.3 has a different spoke pattern then +50mm 5x100.
if the 17x8.5 fits there should definetly be room in the 18 unless the spoke pattern changes. I'm very curious why Volk has changed this.
This is a recent change, as I have seen their page saying the +50mm fits.
Either way it appears these new batches of TE37s require the +40mm offset for the 5x114.3.