Everyone knows that the Viper ACR and GTR Spec-V have already been released and they've both bested the ZR1 at the Nurburgring (The Viper officially and the Spec-V unoficially). There are MANY MANY more ZR1 killers on the way though. The Audi R8 V-10, The Lexus LF-A, The Lamborghini Murcielago LP670(like the Spec- V version of the Murcielago),
Ofcourse there are cars for a long time ago that are now antique technology like the Enzo Ferrari, Maserati MC12, Pagani Zonda F, etc.
Hell, the fact is that there are many modded GTIs, STIs, EVOs, RX-7s, etc that would CRUSH a ZR1 at the ring, or at the drag strip for 1/2 or 1/3rd the price. This Supra is the FASTEST STREET LEGAL CAR ON THE CONTINENT at the present time with a top speed of >285 mph.