The current issue (September) Road&Track has a summary of all the cars they have tested. It gives the results of their tests of various performance factors.
It shows the XLRV 0-60 at 4.3Sec Viper SRT10 4.2 Corvette (400 HP) 4.5 and Z06 3.6. No test of 0-40 (stop light) but I think the Viper and the XLRV would be nose to nose.

XLR V 0 to 60 is tested to be 4.6 seconds.

Pretty wierd!!
My issue must have a reprint. I just checked it again and it says 4.3sec 0-60,
10.2 0-100, 12.7 qtr mile at 112.3 MPH
Thanks for the correction!