e36 M3 subtle wooosshhingg sound

[JEDI]

Hey guys, I recently started hearing this subtle woooosshhing sound from my car everytime I release the clutch, and even very more subtle when I am down shifting, does anyone know what that is. THANK YOU....

Also, on another note, my MECH and I had a bit of a fuss today because he put PENZOIL FULLY SYNTHETIC OIL in my car, and I was pissed because I F#@&%NG told him to buy mobile one fully synthetic, but he insists it was the same. I am still kinda pissed off. I mean my car is 138K miles and I don't want to be messing around with different types of oils you know, just the one recommended. So what do you guys think, is he right????? im going to do my own research. but let me know what yalll think...peace

[MMTuning]

Sounds like a leak in your air intake somewhere. This can create a whistling or whooshing.