Well, as far as KORG USA, they would not not know anything about a product that is KORG Germany, although KORG USA whenever I email them I get a very quick response, even recently about a month ago i got answers to many of my questions, now as far as compatibility it should be 100%, the KORG PA800 and the PA2X are made in Italy and it doesn't matter whether you buy it in Germany or the US, the only thing is that you can buy the KORG PA3X Musikant from Germany that is the only thing proprietary, about the hard drive I have no clue although logically you should be able to install it in any PA3X, which I guess is made for a non-musikant PA3X You can email Music Store export@musicstore.de and ask them, they will be more then happy to answer any of your questions.
GOOD LUCK!
Edited by vangelis (05/03/12 12:55 PM)
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Currently main setup on stage are:KORG PA4X,PA1000