I bought a 2011 Crown Vic with 17" wheels. I have 16" rims and tires from my 2007 Grand Marquis. Can I use them on my 2011?

NO. It will throw out the speedometer reading, and the primary ECU settings for the transmission RPM and cruise control information (when you use cruise).

YES! It won't effect your speedometer reading AT ALL because the speed is read from the Anti-lock speed sensors on each wheel instead of from the transmission like it was back in the day where our "friend" obviously lives. If you take a tape measure and measure the circumference of the 17" and 16" wheels - with the tires mounted, you will find little or no difference. How would I know? In our fleet of 2002 to 2013 Crown Victoria Police Interceptors, we have 2005 and earlier cars equipped with 16" wheels and 2006 and up cars equipped with 17" wheels. The only "difference" you may see is in the offset of the wheel centers but don't worry about that either. BTW - the 16" wheels are less prone to damage - we changed out over 300 17" wheels last year - cops are kind of hard on stuff.