My rear right coilover is clunking like crazy. The left rear does not make the same noise.. the noise sounds almost like a big metal disc has a centimeter of gap'age and is clunking up and down. Makes noises going over speedbumps.. going over little bumps in the parking lot.. pretty much all the time. So this is probably not normal but I'm wondering what it is, if it's an easy fix, or if I should take it back to the shop and get it looked at.

 

Get the rear wheel off and check the spring. Also check all the suspension and shock bolts on that corner to make sure nothing came loose. The spring is more likely to make noise than the shock due to the inboard mounting arrangement on the Z.