See the parts of a new interview of the GT man.
Source: http://www.gamestm.co.uk/interviews/ps4-makes-incredible-difference-for-gran-turismo-says-yamauchi/
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"Everything will be running naturally," Yamauchi assured us. "PS3 was much, much more difficult. The high quality of data that we have being rendered on the PS4 I think is going to make an incredible difference."
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"For GT7, myself and my staff have a clear vision: to do everything we couldn't do in GT6. We want to make it very Gran Turismo. By that I mean it's going to be a game that matches the very era that we live in, in 2015 or 2016."
Source: http://www.gamestm.co.uk/interviews/ps4-makes-incredible-difference-for-gran-turismo-says-yamauchi/