For anyone who ever wondered if there was a way of wandering territories like El Corona, or Chinatown, Easter Basin or Garcia (which are all owned by gangs you normally can't engage in turf battle). Getting rid of the gang the own these territories involves many glitches that weren't discovered by me and they were very helpful. Also, it should be noted that these territories will be owned by GSF after getting rid of theses gangs and cars like Manana and Buccaneer will be impossible to find outside of Vigilante (and Firefighter i think) if you get rid of the Da Nang Boys (Tampa still can be found in a spawn point next to Jefferson motel).
Now for the method, it is very helpful if you look exactly how territories are distributed, Pdescobar map is ideal for that:
I will explain how to do with examples:
First do the satchel glitch to get COM4 (look in the map to find it). You don't need to actually use satchels here, you could just lure vagos or ballas that attacked a nearby territory by walking with them following you or drive a BP car and when there kill them with a weapon of choice.
Second do exacly the same thing, but instead of killing all fof the attackers kill 3 or 4 and leave the remaining alive and just wait for a message telling you that it took so long that you lost influence. You should wait somewhere else while this doesn't happen so no one will run over them or kill them. After this COM4 will be a shared territory between you and the attackers.
Third, once again wait for any territory to be attacked but instead of going to the attacked territory to lure them to COM4 or to put satchels in them just ignore this territory and go directly to COM4 and kill some gang members thats share this territory with you and then wait for the message that you left the attack uncheked and lost influence, no COM4 should have a darker density of the enemy gang. (I don't know how many gang members you need to kill, i think 5 should be enough, but I usually kill 10 or more. Also beware of phone calls, Denise or someone else could call you and cancel the attack and you would have to wait for another, you can wait inside a car after killing enough enemy gang members to prevent this).
And finally do the satchel glitch twice on LMEX1B or LMEX1A, if you do only one time you will activate the territory but it won't be attacked by ballas or vagos, you need to do 2 times for them to do so.
Now you just have to wait for them to attack the territory you chose to do the satchel glitch twice also and leave it unchecked but this time don't kill any gang member while you wait. Let them attack this territory and leave it unchecked two times, because if you wait them attack only once this territory will be shared by GSF, varios and Ballas or Vagos (whoever attacked of the two) and you won't be able to start a war. After they attack just start and take over this territory to then be only owned by GSF.
To increase the chances of the enemy gang attack the territory you want to do this I sugest you take over most of the normal territories so there are less territories ballas or vagos can attack or you can also wait for a territory to be attacked in a territory that can be attacked but you don't want to, because if you wait where gang members would spawn if the said territory would be attacked they can't attack it.
I tested it and work everywhere, but it is much harder of doing this in San Fierro. If it is not very clear just ask something that was hard to understant and I will try to explain again.