First of all,
Welcome to MK6 GTI.
as far as i know, the stock touchscreen enabled headunit by Clarion does not have language options.
I still have the unit, i went to each and every option, and just gave up.
I now use it as a glorified bluetooth receiver and just play music through bluetooth from my phone.
Regarding the tensioner, where are you doing them at what price?
might want to hit up John / Vert (on the forum) if you haven't already.
Cheers,
Peter.