Steve,

Bias-ply tires do something similar to what you are describing, but I'm sure your 205/50/16's are not bias-ply. When I bought my current '67 122S, the P.O. had bias-ply tires on it. I simply could not believe how they followed each and every groove in the highway! Left and right tires in seperate, non-parallel, diverging grooves had a really interesting feel to it. Like a wishbone being spread apart!

The behavior had to have been exagerated by the loosey goosey front end, which I rebuilt soon after purchasing the car, but when I changed the tires, just that alone eliminated most of the behavior.

I assume you checked all the connections and bushings. Could you have torn, or otherwise broken down steel belts in one or more of your tires, from the hard corners and autocross?

gary - '72 ES, '67 122S