The 2003 Crown Victoria Police Interceptor has the 4.6L SOHC V8 engine in it, rated at 239hp and 287ft/lbs of torque. The tranny is the standard ADOE, and the power is put to the road through a 3.27 rear end (Trac-Lock and Traction Control are optional).
It's been a very long time since police cars got special motors put in them. Police cars just don't need to be the fastest thing on the road. They need to be quick, roomy, reliable and (most important to municipal bean counters) relatively inexpensive.
There are no special "police chips" put into them that make them faster. I'm sure you've all heard the rumor about the special chip that the police pull out of the ECM before they auction the cars off to the public. There are some subtle ECM programming differences in the police packaged CVs -- higher shift points, firmer shifts, higher or eliminated speed limiter, higher idle speed, etc..
The things that make the police cars different are very subtle: High output electrical systems with special equipment wiring and power distribution panels; Certified calibration speedometers; Spotlights or "spotlight prep" packages; Electrical bonding straps; etc. It's almost all funtional, rather than performance changes.
The "Special Service" vehicles (like the SSP mustang, and the B4C Camaro) are used as special pursuit vehicles. They have some special functional options installed (speedo, high capacity electrical systems) but they generally fail to meet police durability requirements to get a "police package" label. They are pretty poor when it comes to general law enforcement use, but they are great for highway pursuits which is their specialty.