It could be out 2013, but first that's assuming it'll be on ps3. If it's on PS4, then I highly doubt it'll be out 2013, I don't even think ps4 will be out by christmas 2013.
Also, this is PD, so their could be delays even if it is on ps3. THere's no real reason for there to be, but like I said, this is PD we're talking about
At first, I had hoped GT6 would be on PS4, but honestly I don't really want buy another system. I really never want to spend more than 300 on a console, and that means ps4 is a few years down the line for me. Though I know those PS4 graphics especially when GT whatever comes out is gonna look insane. I mean look how GT5p looked, and that was only in 2007. PD really knows how to get the best graphics possible out of a system even at an early stage