On the basis of information from readers who have had the 'fix' done, the best advice I can give to you is not to have it done. Think about it. The engine is high NOx, but was programmed to be low NOx only during the NEDC emissions cycle. That was the 'cheat'. Any electronic reprogramming done to it to make it lower NOx without considerable other modifications will change its driving performance from optimum to something else. One reader discovered by putting his car on a chassis dynamometer both before and after the fix that the revs at which usable torque is developed had risen by 300rpm. With a diesel engine that would normally be running between 1,500 and 2,200rpm, this makes a very significant difference and is the reason for so many reports of rattling from the EA289 Tiguan 2.0 TDI when conservative drivers change up a gear at the engine speeds they usually upchange.