The pro uses the Yamaha EX5 76 note keyboard which should be liked by all. It includes expansion ports for Yamaha's plug in modules which will allow you to add more polyphony and piano's, DX 7 sounds, An (analog physical model sounds), VL (virtual Sax model sounds) and another XG sound plug in. Every board you add is like adding another sound module because you are adding new parts, new sounds, new effects and most importantly, more polyphony. I've been told by Yamaha to expect the list price to be around $4000.00.
George kaye