I think Mercedes E500 W124 from the 90s is a very nice getaway car. Very discreet with plenty of power to carry 4 people. BMW 7 series or M5 will also be a good choice. When it comes to getaway cars, 2011 movie “Drive” with Ryan Gosling probably showed the best take on getaway cars. Gosling’s character drove heavily modified silver Chevrolet Impala, which according to the movie “is the most popular car in the state of California”