Mario,
The weight is 30 lbs. A hard drive can be installed but unlike the PA80 which is user installable, you have to buy a hard disk mounting kit from Korg and the keyboard needs to be taken apart to install it so they suggest having a service center install it. There are 160 user locations for performances which include everything you can tweak and change on the keyboard and styles and songs can be played direct from either floppy or hard disk so amount of flash memory is not an issue. You can store 48 user styles but hundreds can be played direct from disk as well.
George Kaye
Kaye's Music Scene
Reseda, California