I changed the DV on my 1.8T AGU not long ago. Easy enough to do, if you pop the engine cover off and follow the intake the DV was at the back of the engine in front of the bulk head. Follow the intake pipe and it should be on there somewhere.
Take the jubilee clips off and swap the new one for the old one. Standard one will be a black plastic one, with an entry on the bottom and one the side. There will be a small vacuum hose coming off the top.
Its a 10 minute job, well it was on mine anyway!.