[Jhiieri]

Granades and Turrets can be implemented, but it'll be tougher to code. Plus since it affects only gang wars, the result will not be felt as quickly. It is a good idea though. Maybe grenades and turrets can replace or combine the gang's Hardening and Combat rating in a way that besides giving bonuses it can add a random effect like 2% of the time you attack/defend.

Ideas off the top of my head:
Grenades:
Lucky throw results in smog buildup. Rival gang can't attack for 5/10 minutes.
Grenade in the oven. "X" Rival gang members take "x" damage

Turrets:
Blanket Return Fire. Rival gang can't attack for 5/10 minutes
Gas Tank Shot. "X" Rival gang members take "x" damage