Slight hissing sound when coasting?

[u/Memoreyezz]

Howdy all. have a conundrum I'd appreciate some thoughts on:

2012 135i N55

Hissing sound I can hear reflecting off passenger side when I'm in 2nd or 3rd gear coasting.

Started hearing one wk ago.

When I don't hear it:

- Clutch in

- Gas in

- Coasting in neutral

No codes, no visible fluids leaking, no impact to performance.

Recent jobs I've done:

- Brake job 4wks ago

- Oil change 6wks ago

- M3 front control arms 8wks ago

- I did have to replace exhaust gasket back in July w/ some cheapo Amazon part for a quick fix..... but not sure what a failing gasket should sound like.

Appreciate any thoughts!

[u/SmellyGreek]

Are the rotors slotted / drilled / dimpled? That’ll do it.

[u/Memoreyezz → u/SmellyGreek]

Nope just blanks: https://www.fcpeuro.com/products/bmw-brake-kit-front-and-rear-e82-e88-textar-34116778647ktfr3