I have another suggestion, just to mix things up a bit.
Cash regulation.
Say each person starts off with $5000. Then, everything they buy, costs them money- so, from coffee at the cafe, to Connan having fuck loads of guns.
Also, it means that if Dom whores himself out, he actually gets paid for it, or if Kitsune does a mission, he gets cash for the kill. Also, I figure we could make this more detailed if you guys are interested- I have a few thoughts on this, but I want to know what you think of it as an initial concept.