Seat noise
Short answer: Not sure if you are describing same noise or problem I had, but before going to shop, I would suggest experimenting with some different seat positions.
Long answer: I had a seat noise on my 07 QP Sport only I didn't recognize it was coming from the seat! I took it in twice for repair thinking it was a rattle coming from the door or window when going over uneven surface. VERY annoying.
They finally traced it to the driver's seat. They did some sort of adjustment but it didn't completely resolve it. What I discovered by trial and error was that the noise only happened with my seat fairly close to the stearing wheel. (I took a BMW introductory driving course when I got the car; couldn't afford the Maser course

The result was that I moved my seat quite a bit forward from what I was used to in pre-Maserati driving life). I just moved the seat back a tad and the noise disappeared. It recurs whenever I move the seat ever so closer to the wheel. I assume the undercarriage of seat must be rubbing on something when up close to dash, but I have yet to discover what in order to adjust or move the offending bit to get rid of the sound no matter what seat position I choose.