the A3/TT (and R8, which uses similar interior bits) have a totally different infotainment system to the other PQ35 chassis cars - not entirely sure why considering Audi's stuff is WORSE. on that basis i very much doubt it would be an easy task to get an Audi wheel working. DSG paddles i'm sure wouldn't be a problem but i doubt the MFSW buttons would.
i don't know for certain but i can't see any reason why wheels from the other PQ35 cars wouldn't work tho? as far as i was aware the Octavia, Leon etc. have the same sat nav and trip computers bar tiny details?