'94 960 Sedan. When viewing the car on a level surface from the rear, it's noticable that the right side sits lower than the left. Now I'm getting a burning rubber smell where the right rear tire has contacted the fenderwell. Are there multiple potential causes (e.g., sagging springs, collapsed shocks, etc.), or is this pretty much caused by one thing?

I'm thinking I'll probably need to replace the nivomats, which, from reading this board, I know can be rather expensive. If so, what is a good source for the parts? Can I convert to a more conventional (i.e, cheaper) type of shock? And is this something a DIY can do, or does it require special skills / tools?