I think radrock has it about right; the 2400 series (followed closely by the 2600) came out within a year of when I bought mine in 2007. I suspect the first of the "zero percent" incentives, which were offered then, were an effort to move the 2300s out before the newer ones arrived. And, of course, now they have some "new" model numbers.
As with any vehicle, the first model years were subsequently "improved" with various tweaks over the years. Mine, for example, has a factory-installed transmission oil filter guard, whereas the early models didn't; a lot of folks added them to their tractors. There were probably other differences as well-- seems to me the FEL joystick control is a bit different on mine, as compared with early 2300s. I know there were some problems with muffler breakage on some model years, but I haven't had any problems with mine.
As far as a price, I wouldn't dare say-- but you could get a pretty good idea, I suspect, from dealers and/or ebay. Ask around. I don't think 320 hours is very much time at all for these tractors, but it really depends on how well it was taken care of, too. WBB
