"Play Import CG games" questions

You know that trick that u replace a gc game with an import to play the import on the wii, i got a few questions:

Does it mess up ur wii in any way?

does it mess up the game or disk in any way?

for *** games, do u need a *** memory card?

will the trick work on an american wii (cause so far i've only seen it used on uk wii's)?

are there some games it wont work with?

thanx in advance. I really need the answers.