Asked the VAG guy I know about this and it seems there is something to what Robin Hood is saying. Early examples for the RS4 (first car with this engine) had a glitch which was present in the first few months of production but said that a recall was present to fix and was out more than a year ago.
Couldn't tell me how much of a drop off in power it was but that it effected the very top end of the rev range so was not noticeable in almost every situation other than full throttle acceleration runs.
Apologizes RH.
