165mph in a 94-95 supra twin turbo, for about 3 miles. So fast it was scary, and it had a lot of room left in it's power band. Not driving, although I did get to drive the car, which was an experience in itself.
I rode in a sub-10s 86 mustang with a 302/331 stroker, supercharger, blahblahblah, ~640HP at the wheels. The acceleration in that car was so insane that it was truly frightening -- in particular I recall coming off the freeway from doing 150+, merging onto the eastbound road (Uintah) and fishtailing / having no traction in the back for well over 1/4 mile, as we seesawed up the road, down a hill, over a bridge and finally fishtailed around a stoplight. Simply incredible. Not driving, and don't think I *could* drive it, and I do a lot of wheeling/daily driving and consider myself a good driver.
The fastest I've ever driven was in a buddies 1950s peice of crap studebaker that was a total sleeper. Had a blown 454 in it and 4 carburetors! I was hauling ass to denver and my truck was dead, so I had to really make up for time. Did a little over 120mph from Colorado Springs to Boulder (~110 miles) -- that was the day I found out that you can go from Downtown CoS to southern denver in 1/2 hour, and that you *can* go 110 miles in under an hour.