We drive Crown Vic Police Interceptors. They are 4.6L V8's. The motor officers ride Harley Davidson Road King Police models.
The CVPI does just fine for 99% of the work we do. Most of the time I am driving 20mph down alleys or 30mph over curbs and through housing project courtyards (that's my version of a foot pursuit). I have yet to loose a vehicle pursuit due to a lack of power. If the other vehicle is faster, traffic and driving skill usually even the field. Also remember that we have radios and Spike Strips. For a big honking car the CVPI handles well.
We have looked at smaller cars (the Chevy Impala) but they were a dismal failure. I wear 20lbs of crap around my waist and have another 150lbs of gear in the trunk. You run out of room fast.
We will probably be going to the Dodge Charger next. The have the V6 putting out more power than the CVPI and using less gas. Plus the interior room is supposed to be very good. We will see how our test model holds up.
The Harleys are totally for show. There are sooo many other options that would work better. Tradition dictates that we ride Harleys and wear polyester. 
As far as American VS. Imports. How long do you think the politician that OK's purchasing imports would stay in office? The only exception being a vehicle from one of the Domestic Import factories. (i.e. Toyota is just up the road) The problem is they don't make anything suited to police work.
John
NESBA #218
CBR 600 F4i
Built it Frame-up.
Gear: Shoei X11 Bostrom Rep, Teknic Chicane Jacket, Teknic Violator Gloves, Sidi Vertebra Race Boots, Teknic Speedstar Suit
Mods: Scorpion Carbon High Mount, PCIII, Supersport Undertail, CA Integrated LED Taillight, Targa Cowl, LP Short Stalks, Pyramid Hugger, Shogun Frame and Bar sliders, Corbin Saddle.