I take it then that switching the HD shouldn't be complicated. How about the memory expansion, though? Has anyone ordered it? Sometimes my Audya doesn't respond on time when I switch registrations on the fly. It's quite rare, yet seems to happen more often when the styles involved have lots audios in them, such as different user audio drums in each arranger, plus live guitars and the like. I speculate it's a memory issue, because it comes back by itself after a few seconds or right when I press the fill or break button or stop the style and starts back.

Ketron_AJ said to me in a private massage that the upgrade fixes the audio timing issues because they reworked many of the loops and slightly revised the software to load differently. So my question is, does the memory expansion make things better for you? Originally I was under the impression that the only memory expansion is of 256MB RAM but then noticed Ajamsonic Master Manual mentioning that the optional RAM is either 128 or 256MB. Certainly, I wouldn't want the smaller one...

I see in addition that there are some improvements on the second version of the Upgrade so I'd presume they send the automatically the latest one - am I right? Anyway, thank you all for the informative responses.