Mk5 wheel is pretty easy and if my attempts fail I'll go with that.
You can use the Polo airbag with the Mk5 wheel. It's physically the same, apart from being a little shallower at the back. Apparently you can't notice it. Using the Polo airbag takes all the complicated parts away, no wiring.

I'm currently surfing ETKA to find the slip ring part number for the 9N3. From first glances it looks like it will physically transfer over, I'm just trying to collect all the modules that need to interact with each other. Still trying to find info on if I'll have any probs with the cruise control playing nicely.