Rod,
You were close. According to my calculations at 6000 RPM the speed would have been 154 mph. I have a 6500 rev limiter and this calculation would have been 167 mph.
Anyway you look at it, both of these speeds are too fast for a Unique running Goodyears. I had them squeeling on all the corners and could feel the tires fold over on the wheels and settle in each time I entered a curve. After reading Alan's thread about his tire coming off the wheel and flipping his car, I count my blessings even more that I didn't crash that day.