Personal stereo 
Garage to tune up cars e.g. added weapons, paint jobs, NOS 
Refuel cars (do fuel runs!) 
Civilians committ more crimes (e.g muggings, shootings, kidnappings, holding up stores) 
Have cops be more responsive to civilian crimes (e.g. have cars instead of one cop on foot) 
Get bonus for stopping a crime (have a go hero bonus?) 
Start gang wars (maybe a 100% bonus - lead your gang on jobs into other gangs turf) - Good multiplayer option!!! 
Run your day to day businesses 
Have to defend your gangs turf from other gangs  
Air ambulance missions in a heli!! 
Skateboard park like tony hawks - do tricks and get money for it - works with bmx as well 
Have gangs do drive bys on other gangs and you 
See characters around in the street sometimes - talk to them, fight them, or ignore them - players choice 
Cops and gangs have shoot outs  
Mission where you take hostages and have to escape or stop cops getting in