I needed a new project anyway, but this video kinda inspired me to work on a device that does more/less the same thing. A lot of the hard work (IE: CAN gateway interface information) has already been done for me here: https://community.comma.ai/wiki/index.php/Volkswagen#Overview
If I can get it to a somewhat workable state I'm happy to put it on github for all, but it won't be quick given my work schedule.
300EUR for a really buggy box like this is... not happening for me.