I know this has been done before and I also know the whole '**** in the tank claiming this and that'....
However I know my injectors are dirty.. On a cold start it's jerky and lacks power ever up to 2500rpm which is all I rev it too when cold. I've had a crap idle and revs take a while to normalise when hot..
I thought I'd try the above and well in pretty impressed I've tried to be as objective as possible and reset my mpg after running the car at a steady 3k before and after.. I'm seeing 2 mpg more after doing half a tank of bg 44k and my jerky cold driving had disappeared.. Pretty impressed my car has done 80k.. I wouldn't recommend it on a new tfsi but if you are having the same issues as me go for it, like having a mini remap.. Impressed! Power feels much better..