GT3 sold far more copies in both America and Japan in a shorter period of time than SSMB did. I think it sold more than 1 million in less than a week in both America and in Japan.
But as Ryu pointed out in another thread, Nintendo isn\'t lying or "riding the BS train." They are only wording their sentences cleverly. For example, they said something along the lines of, "SSBM is the fastest selling game for any system released this year." The key word was this year. The PS2 was released last year, so it is not included in Nintendos statistics.