Secian

Thanks for the help Gio. I just did a backup of the meta file and overwrote it, made the tint and handling changes and now no more radio. 

That's normal, <audioNameHash /> is the default.  However, I asked because changing the namehash to, say, "baller", so the car sounds similar to a Tahoe, will result in the civilian radio playing.  What cars did you install?

You said you installed a vehicles.meta file.  Go into the meta and double check all of the namehashes just to be sure.
 
Though, what you said also works. My advice, if you're playing LSPDFR and in a police car, you don't need the radio anyway.  I recommend just turning the volume down in the settings.

Try running it in forced windowed mode from the RPH settings.