You've read an old article that has been denied by Kaz, Sony, PD, etc etc etc over and over.
GT5 IS NOT... I repeat IS NOT coming to PC.
Remember the majority of these rumors didn't get started as GT5 to PC rumors, but as GT5 to "Multiple Platform" rumors, which isn't entirely false. See these rumors were started back before GT: PSP was even announced, so yes the "Multiple Platforms" rumor did turn out to be true with the PSP which was an obvious letdown for a lot of people.... Somewhere along after that the rumor morphed into GT5 to PC..., but that's not going to happen at all, well unless you count the Dev-build of the game, and well if you count that then every game is a PC game l0l.