These both cars belong to the VW group Veyrons production has been stopped because of the high CO2 emmissions and Reventon in terms of speed does not match Veyron.
Millions of pounds were spend to bring the idea of veyron to life Reventon has been tuned by Audi and the downscale version of Lambo is Audi R8..
Veyron is like concord where as lambo is just another Hyper car tuned up further for better results my vote just like always EB