These cars need a 4 wheel alignment-- don't let the guys at the alignment shop tell you they can't adjust the rear-- if they tell you that, you are at the wrong shop. Chain stores are often less than ideal-- I'd try to find a mom & pop shop that specializes in alignment rather than having some kid who spends most of his day rotating tires and changing oil do the job. I just had my 2000 V70 aligned and was surprised at what a difference it made in how it handles.

I've had bad tire wear with bad ball joints that didn't clunk but were well worn. The only way I could tell they were bad was by checking the axial play after unloading them with a pry bar.

Good luck!