to a degree they were mate, the biggest differences in being, model they were going to be fitted , as the 550 had the transmission running through the cab , as opposed to as good as flatish floor in the 590
driven a few 575's with different wheel sizes, most with 32"rims fitted but apparently most dairy farms just bought what was stocked , where as the arable farms usually went into the spec sheet a bit more carefully
wasn't convinced with the 4020axle at first mark , but am coming round to it all coming together nicely :)