Never used one of those or seen one in the flesh, BUT from the pictures I've seen, the motor is a pretty standard foot mounted job, which gives plenty of choice. Given the capacity of the machine, 750w would probably be the absolute lower limit, but still useable. The upper limit for reliable use on standard domestic circuit would probably be around 1.5kW (though I get away with 2.2kW using old, heavy motors which appear to be less greedy on startup). RPM you can work out from the saw diameter, necessary peripheral speed and the size of pulley on the saw spindle. Of course, depending on the space available (generous, again from memory) you could choose a motor pulley of appropriate size to accommodate the RPM of whatever motor you fit.
Hope this helps.