Having now tried it, the column is fitted with an adapter that increases the spline to the larger size used on the mk4 Golf etc. I test fitted a Passat B5.5 steering wheel. Not sure what to do with the airbag wiring and horn ring, but I guess a VW/Audi/Seat/Skoda wheel will have the same fittings. Looking at the OMP hub catalogue, it suggests that a Porsch 997 wheel is compatible, not that I can afford one. They cost more than the car ;-)