Some of the main differences are; aluminum driveshaft and mod's
to the transmission, EEC-V has been modified to increase idle speed
and provide higher shift RPM's, along with raising the top speed to
129 MPH, extra reinforcements in the frame and roof, Police
Interceptor springs and shocks, auxiliary transmission and power
steering coolers, heavy duty cooling package with a viscous type
fan, heavy duty interior (seats, etc.), calibrated speedometer,
Z rated tires, auxiliary connectors for installing equipment.......
I'm sure I have forgotten something, but those are some things
that I remember offhand. Also, the CVPI's (police interceptors)
have the option of going with a posi rear, and the newer models
have removed 'electronic traction assist' as an option..