89 300E all over the road
 

Just got a 89 300E from inlaws and it is all over the road when you increase or decrease speed, has a mind of its own. Been reading some other posts about bushings on the rear links rear diff mounts and possibly front strut mounts. Where should I start?

That's easy. You start with engine off and car sitting normally. Yank and shake each wheel in turn, gripping at 3 and 9, then again with a double-grip at 12. Report back what you find.

Steve

Start with the rear suspension. The torque struts and/or the supporting joints WILL cause the symptoms you describe.

all over the road
 

See how much free play is in the steering wheel with the car turned off. My 85 300 td had a lot. I don't know if your's works the same but mine had an allen screw adjustment on the steering box that you turned counter-clockwise to take up the slop. This fixed mine and didn't cost anything. I went from 4 inches of free play to 1. Big difference in handling. Good luck.