With cold start, when I shift from Park to Reverse, or reverse to Drive.
It makes a weird scratching/squeak noise from rear suspension. Also when shifting from one to another, it seems like transmission moves up and down.
Is this normal?

Also at complete stop, as I release the brake very slowly, starts making noise as I slowly release it!

 

This happens with my dad's Boxster, especially after the car has not been in use for a couple days, the brakes squeech and halt very hard, feels as if the brakes were going to fall off... But I would drive it around for a little bit and it would go away, could it be that you rarely drive the car, and if you drive it daily, you might want to see what the dealership says before you agree to any charges, they rape you on brakes at mercedes, my brake job on my ML320 was a whopping 720 bucks. I was quite upset. And i thought it was only squeeky brakes, hah... Good luck!