Disklavier

I ordered a DU1A today and the salesman showed me two types of Yamaha powered 
speakers.  One was a larger 60W model with about an 8" speaker that he 
recommended using alone or two 20W speakers to use on either side.  Each option was 
about $650 which I thought was kind of expensive.  I have about 6" on the 
floor on either side of where I will place the piano so the bigger speaker 
probably won't work anyway.  The larger speaker sounded nice but I never heard the 
20W models.  Does anyone have thoughts on what speakers I should use?  Any 
thoughts on placing them on the floor or on top of the piano lid (or I could 
wall/shelf mount 2 small satellites)?  I thought I understood that the speaker 
output is stereo and I would think that two speakers would be superior.  I'm sure I 
could get good powered computer speakers or a 3 piece powered satellite/sub 
system from Bose or Cambridge Soundworks for less than the $650.  Perhaps this 
price could be negotiated too since they came down a good bit on the piano 
when they realized I was shopping two other dealers.  Jeff