Kotaku writes:

"When we visited Gran Turismo creators Polyphony Digital in 2006, president Kazunori Yamauchi previewed what would become Gran Turismo HD, the first "real driving simulation" for the PlayStation 3 that would offer 770 cars and 50 tracks for download.

At the time, Yamauchi called it "the GT version of iTunes," letting players buy the barebones Gran Turismo HD Classic, the download more than 5,000 pieces of content to expand upon the game. That idea was scrapped in favor of a freely downloadable Gran Turismo HD and Gran Turismo 5 Prologue."
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