New calipers and pads?! I seriously doubt you need those, and even more sceptical that they have anything at all to do with the problem you've described. Rear shock top mounts sometimes wear, but can be difficult to diagnose; jack rear up, try and lift wheel vertically: there should be no free play.
Don't take offence, but are you sure the noise is from the rear? front suspension wear is far more common (upper/lower wishbones, drop links, anti-roll bar bushes). I get a lot of people complaining of a noise from the rear which invariably transpires to be front upper wishbones; it's surprising how noises can distort and resonate inside the car.