Hi - I am in the process of 'aquiring' a car for a job we have lined up. It needs to be a big car with lots of power. We may well have to outrun other cars, and so have whittled our choice down to two.
The Audi RS6 or the Mercedes AMG 55 Estate.

Has anyone had experience with either of these cars, and if so, which is the fastest and safest at high speed?