The KN6500 is an upgrade of the Kn6000 is is done by fitting an expansion board (easy job). There are several kn60/65's for sale on ebay for around the £350-400 mark and are very good value for money.
They are an excellent keyboards and a range of styles can be obtained on the net and they will play styles from previous Technics keyboards e.g. KN5000 excetera. Personally I would recommend the KN7000 which is well worth paying the extra money for, It still can hold it's own against the latest models from other manufacturers.Have a look on Bill Norries website: www.willumspages.co.uk. Bill is the expert in all things KN.

peter b