I've had the speedo pegged and then some, racing a modified G35 coupe in the rain on Sawgrass Expressway here in South Florida. I can only guess that it was somewhere around 140 (based on RPM and past race experience). It was very stable up to that point, but then the hydroplaning caused me to let off the throttle ... sssqqquuuiiiiirrrrrrllllleeeeyyyyy ... BTW, I smoked him.
Cool guy though, gave me a thumbs up as he exited in Coral Springs ... at least I THINK it was a thumb(?).