As far as I can determine the FXR-SP, Convertible, and FXRP were the same, regarding frame and suspension.
The Convertible had soft removable saddlebags and the rear turn signals moved off the fender struts to the sides of the license plate. It also had, I believe, buckhorn handlebars as opposed to the drag bars on the FXR-SP. The police bike had the lifted suspension, and was different in the police specific areas such as seats, bags, handlebars, and fairing. Basically, not a lot of difference and if you want the raised bike, you can always buy longer fork tubes, front springs and rear shocks, and do it yourself.