I second what Mr. Hyde says there, I drive Police cars to and from the dealership all day. I have ridden in original Crown Vic's and the Police package and their is nothing different apart from the heavier suspension, more expensive (albeit them nearly indestructible rims), and large tires. Their is no performance gain other than shift points and maybe a taller top gear which you can really feel when it drops into top gear at 70 KMH, you feel the motor go to sleep .....

Well suffice it to say that with the same people I drive home in our shuttle bus, naturally their must be a few policemen (and women), and they all say the same thing: "How can anyone want to buy a vehicle that is turned on, driven hard, taken over curbs at 50 kmh and then gets parked, awaiting the next person to jump in and do it all over again."
Take my advice and don't get a vehicle who's service life is 100,000 km's or 60,000 miles (or higher) and is then forced to retire; they retire for a reason, no unlike being too much hassle for the department to keep them around.
Police car is fun, but heavy and your parent's won't like the video's you and your friends make with the car either.

My two pennies.
It's nice to have a rolling sofa, but alass to sell sucha thing of beauty is even harder to accomplish because someone has to understand your vision and embrace it in order to work with what you have created. Trust on the fact that a swap is GOLD on resale to those that know nothing and want to drop oodles on a car that will make them the fastest goober on their street.
*Jumps off soapbox*