Honestly, it made no difference whatsoever.
Despite all the 'experts' rolling out VAG Com logs to show increased MAF flow measurements...I took mine to the dyno, and got nothing. Nadda. Nowt. F'all.
I guess it would prevent the inlet hose collapsing - although I don't believe the AMKs were ever prone to that...but it looks pretty.
Oh, and it's a pure **** to fit.
It can't be a bad modification - it's certainly no worse than the standard hose...but don't go expecting any power gains.
I can't be more honest than that.