I have a 2011 crown vic ex police car, any ideas if i have to stick with the police alternator?

If it's the Mitsubishi 200 amp alternator, it uses a different wire harness than a standard 130 amp alternator, although the wiring is the same the connectors are not. The CVPIs used the 200 amps alt to keep up with the heavy electrical demands a police cruiser, but it still put out same voltage. It also used a clutched pulley that is controlled by the PCM. As I understand switching back to a 130 amp alternator is common among fleet operators for retired CVPIs, especially given the price difference between a $160 alternator and a $440 one. If you don't mind hacking the wire harness up to switch to the other connectors have at it. (http://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2578256) There are additional links on that page to help you out.

Dif plug and top 2 bolts wont line up u have to get the bracket off of a regular cv or merc if u wanna be able to put all 4 bolts in.

Find a shop that can rebuild your old alternator.

Wrong -- The clutch is NOT PCM controlled! The voltage is controlled by the PCM.

I'm having a problem with mine too it's making noise I'm going to get the pulley changed to a solid non clutch pulley Hopefully it doesn't affect anything

There are several shops that can rebuild your original alternator. There is also a mod kit to convert to a solid pulley. I have not seen one in real life - don't know if you will have issues. I think any alternator from 2008 and newer can be substituted. Just check for the electronics usage in the car, when making final amperage choice.