Works great, would just note that users can quickly edit the link to point to other languages from German:
German
http://de.minecraftwiki.net/index.php?title=Spezial%3ASuche&search={query}&button=
English
http://minecraftwiki.net/index.php?title=Spezial%3ASuche&search={query}&button=
Spanish etc: ES, FR, JA, NL, PL, RU, ZH
http://es.minecraftwiki.net/index.php?title=Spezial%3ASuche&search={query}&button=
No idea about the search suggestion functionality, sorry. I know Google Suggest by David Ferguson manages to do this.
