Depending where you are in the state, you may not even need or want any upgrades.
DMR is sporadically used throughout the state for PD's. Up by me, Pequannock, Kinnelon, lately Bloomingdale, and Rockaway out west, Vernon, and Hopatcong have it. It is more commonly used for businesses, DPW, etc.
Same with NXDN. Very very few law enforcement agencies use it. I believer Denville does. Again DPW, and businesses use NXDN generally. My town uses it for a tac channel(and even then, it's 1/2 encrypted).
ProVoice is a dying thing. Most notable was Middlesex County for a number of years, and some other agencies. They have since dumped those systems. I know up by me, there isn't any agency that I'm aware of using it.
I personally wouldn't spend the money(you have to if buying new, or if not already installed by someone else if buying used), unless what you want to listen to has those types of voice. Just my .02