We're Talking about what now, editing the "Bybrids" ... what's a "Bybrid"
PS:
If you own a cd, you have every right to make a copy of it and put it on a computer. You just can't sell the copies. And if you get rid of the game (original disc) you're obligated to delete the computer file.
Under "Fair Use" I believe you're allowed to edit anything you own as much as you like... People have been adding content to GTA games since GTA1, and all the way to GTA: San Andreas.
As long as "Progrip" doesn't openly advocate piracy of copyright protected software, I don't think anything he has to say is illegal in any way.