Its top speed isnt as high as the mclaren's, but i prefer the GT1 to the F1 GTR. And this is much better than the Mercedes-Benz CLK GTR, which has horrible handling.
It was quite a bit more than the Careera GT of it's time... they both can do 0-60: 3.6 seconds. One is 18 years newer. The 959 was the best porsche FOR THE TIME in history... I think it was the fastest accelerating car ever until the XJ220 came out in '89.