100 in my Cobalt... just to see if it could go that fast. It had a bit more room to go but there were some cars about a half-mile away in front of me.
Hit the governor limit on my old GTP once... almost 140mph.
If this thread is still alive when I get my ZL1 I'll come back then.
In Ontario your car is impounded if you're caught doing ~30mph (50km/h) over the limit. So you have to be careful.