Disklavier

I just found a couple of Yamaha Disklavier uprights on eBay.  I'm 
overwhelmed with all the model numbers.  One is MX90RBL, 
another is MX101R.  Is there some model number prior to which 
one shouldn't buy?  I've read there there is a pedal problem on 
early models and parts aren't available for  #100 models and 
earlier.  The piano will cost about $5,000 delivered.  Perhaps, I 
should spring for a new one.  What would be a good price?  Any 
other advice?