In the meantime, Polyphony will continue to expand Prologue with additional cars, tracks, and features. Yamauchi couldn't speak to specific plans, but mentioned that an new update is planned for the near future.
With all of the work his company is putting into the next console GT installment, Yamauchi tells us that it hasn't forgotten the long-delayed Gran Turismo 4 Mobile for PSP. He confirms that the game – originally announced at E3 2004 – is still actively in development, although it isn't planned for release until after GT5. That would be 2011 for those with pen and calendar in hand.