I DON'T UNDERSTAND K2500X+OPTINOS =K2500XS
I WANT A PICTURE OF K2500XS [VERY BIG] CAN YOU HELP ME ?

K2500x is a master controller keyboard
k2500xs is a master controller keyboard with Sampling option install.
k2500R is a rack version
k2500Rs is a rack version with sampling option install.

you can find more information at www.sweetwater.com (pic) or check out www.synthzone.com and click Kurzweil

You may also want to check out:
http://members.aol.com/k25zone/
This should tell you anything you want to know about the k25.