We recently got a 95 965 with 93K. The car is in nice condition. However, it rides pretty rough. My 86 740 is much smoother over bumps. The when the 960 hits a bump (like a small pothole - say 2" deep) you hear the front wheels hit and then the rear wheels hit, and then there is a thud. The thud sounds like the spare tire bouncing. I have done the following:
checked that the spare tire and jack are secure
replaced rear shocks (I do not have the nivomats)
checked the exhaust for the correct clearences and good hangers
there is no stuff under the floor panel in the "way-back"
the rear bushings look OK - says my mechanic
replaced front control arm bushings

I do notice that the gas tank (which is huge compared with my 740) sags a little in the middle. Pushing up on the tank pops the sag out and makes a corresponding popping noise. Could this be the cause? How do your 960's feel going over bumps?

Thanks,
Steve