Rear-end alignment? and clunk?
 

The rear wheels on my 300D (about 155k now) appear to be slightly towed in. Also they wear more on the inside and wear more altogether than I would expect anyway. The left one seems to wear slightly more than the right too. The car drives straight and gets ok mpg (24-25 with ac on). I'm thinking something is either worn out or needs to be adjusted. Any ideas?

While I'm at it I have a clunk in the right rear, I can't locate it, I've checked the half shafts, shocks, drive line, everything I could think of. Even tried bouncing it up and down but it only does it when moving, mainly in reverse. It's hard to look underneath for noises on a moving vehicle. Just wondering if these two problems could be related?

Pull the rear wheels off and inspect the sway bar link on each end. When these wear they can cause some noise.
Sounds like you need to find a good alignment shop that is familiar with these cars to inspect the suspension, make recommendations as to what all is worn out, replace as required and get them to align it. You may not even need to replace anything, just get an alignment from an outfit that is familiar with these cars.