Ed - I can't really see why a street car set-up should be unpleasant at high speeds. My car is essentially set up for street/touring comfort - fairly soft, certainly softer than a lot of cobras I've driven. Yet it sits straight and true at speeds up to, and occasionally over, 150mph. (GPS checked). Top I ever managed was 165, and that took several miles to wind up to.
On an autobahn, of course, officer.
No front end vagueness, no drifting, just lots of wind noise. The only thing that bothers me is those 6 little screws holding the windscreen to the pillars. Wonder what kind of wind pressure there is on the screen at those speeds?