Call me a skeptic, but with only one exception in the 10 or so cars I looked at on the supercars.net website linked above, only one had any reference to the car having been actually driven at the claimed top speed.
The exception was the first car listed, a Calloway Corvette. And the reference was not to any reputable test, with citation, from an enthusiast magazine or other reliable source. The documentation consisted only of a claim that John Lingenfelter was the test pilot who achieved the rather impressive (if it occurred) speed of around 250 mph. No date, location, or other verifying info was given If Lingenfelter verified that he did, indeed, pilot the car to that top end, then of course things get more believable right away. Still, I'd like to know how the top end was measured even then.
I remember enthusiast magazines over the years running top speed tests of claimed 200 mph cars, where bona fide testing showed the cars wouldn't do what the tuner/manufacturer claimed. On the few occassions where a car actually went over 200, it was only by a few mph. (No, I can't recall the mags, dates, issues, etc, and I'm not going to take the time to look it up, but I bet many of you out there recall this, also.)
My guess is that the performance stats cited on the web site are taken straight from the press kits for the various cars. For that web site to be of any more value than just mild amusement, it needs to list the source of its numbers. Maybe a few of the cars actually go a fast as is claimed, but even the road going 962 and the McLaren F1 are claimed to be around 240 -250 (if my memory of the site is correct) and that seems unlikely.
In any event, until they can "roll the video tape" and show test results from an independent source - or even in-house track tests - those claims are as valid as the latest stock picks we hear about everyday on the TV.
