The Wanted Level in Angels of Police is exactly the same as in GTA IV, just afew features added. They only apply to free roaming.
Nearby Police will have Electro Batons and Pistols.
Police cars will chase you more often, some officers have Shotguns.
Police in cars will shoot at you from out their windows. Roadblocks are set up, more officers come after you. Some officers now employ Electro Guns.
Unlike both NOOSE and FIB chasing you, only the NOOSE will instead. They come after the player in Trucks, wielding Defense SMGs and (rarely)Defense Shotguns. NOOSE now appear on overhead choppers(Maverick or otherwise), using Defense Assault Rifles, instead of the Carbine Rifle. Some now throw down Tear Gas Grenades.
FIB Buffalos chase after you, with two to four Agents in a car. The passengers use SMGs, and the drivers use AK47s.
Heavier, armored and armed NOOSE will chase after you. Annihilators rule the skies and pilots now shoot at you with the chopper's miniguns. Not one person or car is on the streets. NOOSE APCs will chase you, and most NOOSE will have Missle Launchers.