You should check out the Orchestral, Techno, and Session Expansion Boards if you don't like any or all of these boards-that's too bad-they come standard on the XP-30. If you don't like these boards you may want to get the XP-60. But then you said you didn't want the onboard sequencer. I would say you will need to go to a music store and do a lengthy side by side comparison. Either way you may end up paying for something you may not use or even want.