I really doubt GT5 will be able to outsell GT3. Keep in mind that GT3 was heavily bundled by the PS2 which is why it sold 15 million. If Sony does the same with GT5, then it might pass 15 million. Otherwise, I think it will sell 10-11 million max and will probably be 2nd best selling GT game.
Also, if we don't have another GT game this gen, then the sales will be much better (obviously).
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