Want an almost indestructible Vortex?  You can get one from OG Loc's video
shoot in the mission Cut-Throat Business.  Leave Dogg behind and go to OG
Loc's shoot.  Wait for Dogg to die.  Everything at the video shoot site
disappears -- except the three Vortexes.  Take one and garage it.  It's
NEARLY indestructible.  A few rockets will finally take it out (and it may
have to do with the fire they cause).

I left Dogg in Verdant Meadows.  I went there to get a Hunter, and there's
no room for passengers, so I left his a.s there.  Loc and his Ho are still
at the site.  You can sock them and fire rockets on them and the vehicles
and nothing happens.  I went to the nearby highway to get a vehicle to see
if I could push stuff around, but a message said that Dogg had died, so I
went back to Loc and found the Vortexes.

While the mission is still active, you can get into the vehicles -- but you
can't drive them.  They stay anchored to the ground.

Not sure how common it is to have Dogg die conveniently like that, but it's
worth messing with.

--cleve