Re: the warranty issue:
Just called VW Canada (should have just done that first instead of emailing), d'oh.
They said that 'even though it is an OEM part and is sold as an original part on your vehicle in another part of the world, if it isn't on your vehicle as delivered here in Canada or offered as an accessory by your dealership, then we cannot recommend you install it'.
Ok, so they don't recommend it.
They also said 'if it is damaged in any way we would not be responsible for repairing it'.
Ok, that's fair.
When I asked if they would use that as an excuse to not do warranty work on other areas of the transmission (beside the SS itself) she said 'we are not technical experts. Your dealership is the technical expert and it would be up to them to decide what is responsible for any failure. You should check with your dealership.'
So I will indeed discuss this with the service manager when he returns from vacation. I still like the idea that it is OEM.