The RS7 (with the Sport package and thus 605hp) was tested by a German magazine with approx. 31-32s for 0-300kph. The RS6 was much slower (like close to 40s) - they explained this by the far better aerodynamics of the RS7.

Price, acceleration of the RS7 are excellent. Unfortunately, the Panamera has much better brakes it seems. Also, it has the far nicer interior and also a better styling in general. It also feels nimbler in terms of handling. Also, the RS7 will be replaced soon by a completely new model.

Getting one of these cars would not feel perfect as you always know which downsides your choice has compared to the other Smiley