I contacted Tuning Box for tuning the TDI engines in the Golf, Jetta wagon and Jetta. They make a product "a box" that plugs in the engine bay area. See link http://www.tuningbox.com/ANG/p5ang.php
Check the site out
I need help though. Can someone please supply a close up picture of their 2.0 TDI with the engine cover removed? This is a request they had to ensure 100% the box will work with the US-spec vehicles.