N54 High RPM High Pitched Noise

[thetaobear]

I have a 135i with an N54 engine. At high RPMS (3000+), the engine just doesn't sound too happy. It has this high pitched drone sound coming from the engine bay. I was wondering if anyone has experience with this? Is this normal? I find it very annoying because the engine just doesn't sound too happy when revved really high. I have a 335i, which doesn't have this problem.

The video is here and I start revving at about 19 seconds in. I revved it to 4000 RPM- higher the RPM the more noticeable.

Youtube link:

The video is recorded with the hood up, infront of the car. Very audible in the cabin too.

Some insights are appreciated- I was wondering if I should take it to the shop or not.

- N54 Engine
- JB4 tune or no tune (same kind of sound)
- BMS Dual cone intake
- metal charge pipe
- high/low temp same thing

I recently changed the spark plugs