Here in the States, the Dodge Charger is a popular police car. They choose both the V6 and V8 flavors depending on need. I've been working in NY, near the State Police (highway patrol) and those V8 Chargers really sound great as they fly out of the lot, up the private high speed entrance, and on to the highway. Clearly, they are plenty powerful.
Here in Florida, the State Troopers (highway patrol) have a variety of cars, but it seems the Charger and the Ecoboost V6 Ford Explorer are the most common. I see both operating at incredible speeds. From time to time, I'm flying my Cessna up the Florida coast and a Trooper in a Charger is going about the speed I am. I always laugh and try to fly faster... My plane has a top speed of about 165mph, but I don't always cruise that fast.
As I understand it, police departments make fleet purchases and can get the Charger for under $30,000. That makes it a great deal.