Please give the forum you post your questions on some thought. This topic does not fit into Level Design Tutorials.
Hi there,
modifying the client is not pursued by german law. It does violate the EULA of World of Warcraft though.
Don't expect cops showing up at your house, as long as you don't try to make money out of your modifications.
And don't mind your english skills, there's a lot of international people here who don't count english as mother tongue. Verstehste?