Just wondering what is the best console to play on for this game. (So many different types on the leader board )

So i have been doing a bit of casual practice on this game and lately I have been thinking about getting a Japanese copy of the game so here are my two questions:

1. If i run the Japanese game on a Canadian GameCube but then just re-regionalize the memory card will my runs still be considered legitimate. 2.I may be really dumb but I have been looking for an hour or so and I cannot find a Japanese copy for sale.

Hey so i speed run a few different games none notably well but this is my by far favorite game so I was hoping to start it up so I have a fair few questions to ask.

1. Why are most runners playing it on with rather then game cube is this for actual time save from somthing such as lagging.
2. I have two wii'so and one is region set for Japan but I am unable to find a Japanese copy of the game (is am not too too worried about the cost as long as it is reasonable )
3. Is the all stars category fairly new and that is why there is only the one runner or is there somthing I am missing.

In advance thank you for any and all awnseres and hopefully I will be on that leader board with you guys soon enough.