Gang Wars

[Mustang-man]

Once you finish all the storyline missions you have to take over ALL the rivial gang territory for your territory to stop coming under attack.

All around your hood (purple [Ballas] and yellow [Los Santos Vagos]) needs to be taken over, then there is a little more at the Verona Beach area to take over and then some in the Temple/Mulholland area to take over.

Over in San Fierro's Palisade's area some Ballas have a few blocks where they roam around and across the Golden Gate Bridge at the Bayside Marina the Vagos have taken over some territory there.

Once it all belongs to you you will never get gang wars again primarily because you've completely wiped the other gangs out!