I've been told there is off and on buzzing on the other end with the stock HU Bluetooth too.
I have a 2011 non turbo (but model doesn't seem to matter). I got the impression that when I was stopped, it was better, but with the engine rev'ing it was worse.
It isn't my phone, because a stand alone Parrot bluetooth speaker that I used to have attached to the visor in the old car sounded good. I'll either live with it (I only call family from the car and not for a long time), or I'll go back to the dedicate Parrot BT unit clipped on the visor.