[Chilibit]

Wasn't there a thread or two a few years back about ball joints being a trigger for a wobble (I guess this is a side to side motion on the steering wheel) on Superformance. It was at 60 MPH which is roughly your 100 kph. But I would have thought that Cobra Valley would have brought that up since it was a topic on SCOF if memory serves. Also, Dennis Olthoff suggested an approach to me when I was down there but I forget just what it was. It was an adjustment not a part. I did not have much of an issue and if it crops up I just "drive around it." You might email him at Olthoff Racing.

Edit: Blas's comment about the steering box rings a faint bell. I would follow that path. I vaguely associate that with Dennis' comment.