My reason would be that it was never done before and my car has a lot of miles on it. And I think that it would eliminate the light vibration problem when you press throttle about 5% and hold it I'm no mechanic, but what the hell
After following this thread, I put injector cleaner in my A2 tdi. Done 125 miles since and I noticed I need to push on the loud pedal less than before and the engine seems a bit quieter.
Only 2.7 L/100km last week due to half the journey being wet (only 104.6mpg!). This week (in the dry) 2.5L/100km or 113mpg. I don't think that I can do any better than that!
I'm no mechanic, but what the hell