[Dominik]

I spoke to my buddy in chassis engineering in 1999 when I had the same problem with my Miata.

It appears that a lot of manufacturers battle with this.
He mentioned using a different kind of a-arm bush to reduce the effect.

I can't remember the details and also lost contact since I moved.

What type of suspension bushes do you run? Did anybody try a different version?

Isn't vibration also related to diameter (in addition to speed)?
So smaller tires or bigger should vibrate at different speeds.

This will not really help to find out, but would be intersting to know anyway.
Pity that the US speed limit falls in that range...

Dominik, Cape Town