Mr. Johan
Smash Hero
I do know that Luigi mentions go-karts in a journal entry log. I can't think of another spot in the game that references MK64 (Or SMK, for that matter).
I played Paper Mario 2 again for the first time in a while since I got a new disc. I was a Keelhaul Key last save, and I played it to the end. But I turned the game off before it saved anything, since Endless Play bores me, and you can't face the Shadow Queen and see that awesome cutscene where everyone is voicing there support and wishes out to Mario. Best scene in any Mario game there. Beautiful music to accompany it too.
I played Paper Mario 2 again for the first time in a while since I got a new disc. I was a Keelhaul Key last save, and I played it to the end. But I turned the game off before it saved anything, since Endless Play bores me, and you can't face the Shadow Queen and see that awesome cutscene where everyone is voicing there support and wishes out to Mario. Best scene in any Mario game there. Beautiful music to accompany it too.