9500 v 9510: 10 series has feeder house dust system, shoe adjustment upgrades, 8.1 L motor compared to 7.6 in 9500, more cleaning fan speed in a 10 series and different side shield system are off the top of my head.
9600 is a bigger machine: 11" wider cylinder, 5 walkers instead of 4 and a later 9600 will have a 7.6 rated at 15-20 hp over the 9510's 8.1 motor.
there are many more differences that are year to year and some you won't even find in lit. and with ecu's you can't just switch engines to get more power there are other dif. in coolers and pumps. You could fill up pages with the dif in combines