I see a lot of posts on this site about squeaky rear ends on X-types, I had the same problem. I see a reference to upper and lower control arms. I just got done winterizing my boat and had some left over 75-90 gear lube with the pump on the bottle. I took off the rear wheel and pumped a lot of gear lube into the bushings on the upper and lower dog bones (control arms) on the drivers side rear suspension and the noise went away! The secret is to get it into the bushing area starting from above letting it ooze downward, Try this before you go through the hassle of removing all those suspension components.

 

Glad were able to silence your car, but for it to make noise they are worn to a certain extent. You might consider to replacing them at some point, especially if the tires cant in at the top towards the inside of the car. Keep and eye on the tire wear so that the inside edge isn't wearing prematurely.