Just the once in my 40 on a stretch of empty road now littered with scameras. Not something I ever expect to do again or actually wish to now I am a bit older and potentially wiser (ok and with kids to think of too!). I worked it out once. 150 mph is roughly a football pitch length per second. With reaction times etc, you see it, you will likley hit it! At Silverstone I think the 993 was doing about 150 down Hangar Straight which actually doesn't seem fast as there is a good amount of space around you. Then just before you get to your braking zone, Hans Stuck Jnr comes hurtling past in the works BMW at what seems 50 mph quicker than I'm going and, seemingly effortlessly, takes the corner perfectly. I'm so a crap driver by comparison!