You'll need to provide more details if you wish help. When does the clunk/noise occur? Do you have aftermarket parts in your car? Bigger rr sway bars and/or lowering springs almost always lead to the inevitable "clunk".

Why? Because the suspension geometry has been compromised. Lowering springs shorten the distance from the main control arm (location of the end link) to the sway bar. The lever arm portion of the sway bar SHOULD ALWAYS BE HORIZONTAL at normal ride height. Therefore, if you lower the car, the end links should be shortened the same distance.

In terms of the sway bar, the kink is often located at the wrong side of the car (don't laugh as I've seen it many, many times). There's also very little space where the sway bar is located and the increased diameter often causes rubbing on the subframe. The clue is shiny metal anywhere on the sway bar. Only problem is that to correctly diagnose this problem you usually have to remove the sway bar.

Redcoat Raceworks. Performance parts and custom fabricating for Contours, Mystiques and Cougars. Specializing in chassis and suspension parts. Custom end links, control arms, strut tower bars, engine torque braces, etc.