As per the title, i've just fitted an Evoms v-flow to my S3 today and now i'm noticing a single knock noise when I lift off the throttle and the revs drop. It seems to occur roughly as the revs drop below 1000 rpm. You should be able to hear it in this video:
Audi S3 8P lift-off knock - YouTube
Anybody got a clue as to what might be causing that?