It would seem that I may have to revise my Lords of the Ring article already...
American motoring magazine Motortrend has posted a video of the Dodge Viper ACR lapping the Nurburgring Nordschleife in an amazing 7:22. That's 4 seconds faster than the Corvette ZR-1's record time.
To be fair however, everything in the Viper ACR is adjustable in ways you'd never consider using on the street. The ACR is a focussed track day special with 'customisable' aerodynamics and suspension settings.
In addition, the Viper ACR runs Michelin Pilot Sport Cup tyres, which use a rubber race compound with a semi slick tread pattern. In comparison, the Michelin Pilot Sport PS2 tyres used by the ZR-1 are a regular street tyre. By analogy, if you look at Bridgestone's top-level Potenza RE050A's (standard fitment on the HSV Clubsport R8) as being similar in range to the Sport PS2s, then the Pilot Sport Cup tyres would be comparable to the Bridgestone RE55S tyres used in endurance racing classes (events like the Targa Tasmania) - where street legal tyres are required under the rules.
However, that doesn't take away from the fact that the Viper ACR is street legal. In anyone's language, 7:22 is a blistering time for a car you could theoretically drive to the shops.