Ilija,
G-1000 which I own (and EM2000) allow you to call up styles from the disk (ZIP) instantaneously (or as easily as the internal styles), using the Disk Link function, though there is a general problem calling things up on them (you can see some of my eralier posts in this forum if you want to know my gripes). That applies to most high-end instruments. Korg and Solton allow you to store user styles into Flash Memory, which makes them instantly accessible.
If you really do not neeed the internal styles, you may want to look at Farfisa G7, stores all of its styles in the flash memory, and allows you to replace any or all of them with the user styles.
Regards,
Alex
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Regards,
Alex