The wanted levels in GTA V kind of suck. You've got a police force that is half-psychic, half robocop. When you hit max stars, there are no tanks anymore. What gives?
Enter modders. The Crime and Police Rebalance & Enhancement mod, as shown in this video by The XXI, reworks the entire crime system in GTA. Really, the mod seems to make the entire game much better in my opinion. For instance, the mod makes it so that if you commit a crime without any witnesses, then you get no stars. It also means that if you manage to kill everyone at the scene of the crime before they call 911, you're golden. And if you use silencers, they're actually silent. Furthermore, animals do not report crimes anymore, making stealthy crime an actual option. That's the way the game should work, really.
In addition to this, the mod tweaks the AI so it's not as efficient a murder machine as it typically is — cops, army, and gangmembers are less accurate than normal. Some of that police force will also be women. In general, the police force will have a more varied weaponry and adjustments that make the game feel challenging, but not unfair.
The progression system of the wanted levels is different, too. In this mod, it goes police > tougher police > swat team > FIB > the motherfuckin' army. That means you can look forward to being chased by tanks and intense aircrafts after going on a murder spree, as one does in GTA.