Bear - the short answer is the 900R.
The RX is an acquired taste - bigger, fatter - and no faster point-to-point than a 900. In fact, they could be slower....they were only released for 2 years - '86 and '87. Replaced with the ZX10, lots of updates, alloy frame, downdraught head etc.
I am pretty sure that the '88 model 900R still ran a 16" front wheel. They changed to a 17" front in '89 or thereabouts, I think it was the A7 or A8 model - this one is the pick of the bunch. It is pretty easy to fit a 17" front if you really wanted one. The 900R is definitely more of a 'collectable' model, but the ones worth the most money are the first model - A1 of 1984.
