I know Top Gear tested a white Vauxhaull VXR vs a blue Focus RS. They stated the VXR line is always fast and well made. They mentioned the same limited slip/revoknuckle in the RS is used in the VXR. They liked the RS, but the VXR won their races.
I would like to see a dry run vs wet. I am going to guess that race came down to tires more than the vehicles engine. The VXR might have all season vs the RS having summer rated.