No problem on a smooth hiway, but if there are any cracks or variables in the road surface, the car seems to want to sway seemingly from the rear end. Not sure what it is, shocks and struts look good, but, it feels a little dangerous almost like there is too much steering. Just talkking 55-70mph or a 100Kph average. Anyone know what this is?

 

Shocks and Struts don't "look good", the question is if they are working?
You can do the bounce test, push down on the rear, it should be firm and respond up with no additional bounce. Realistically, pulling the rear shock assy out isn't that hard and you'll be able to physically test the shock.

Also check all the bushings in the rear end, make sure they are in good shape with no play within the rear beam mounting points. Make sure the link bushings are all tight as well.

 

The bounce test for struts and shocks is subjective. They have to be pretty bad to bounce noticably and then that is to a person familiar with doing this. If you have 90K - 100K miles (145K - 160K Km), you are over due for replacement.

 

OP, I had the same problem with a feeling of "shiftiness" when cruising on the highway and where when making slight bends in the road at highway speeds, the back end would feel loose.

I replaced all four shocks/struts since in my case they had been in use well over 100K, and the problem is gone completely now.

 

the car is at 210K and bounce is very evident, so time to replace. Hard to get off at used one's at boneyard without pulling the caliper bracket and rotors off, very labour intensive for what otherwise is 3 bolts. thanks all for your advice.