Sound comes from here , i'd describe it as a somewhat metallic buzzing
Tried to record it revving the engine up in neutral but is very subtle in the recording: link
Car's performance/MPG is not affected.
All mechanics I talked to said to drive like this and if things go worse then bring the car in. I don't want to wait until/if car blows up

Car is 09 1.4 TSI twincharged 160 hp