I was wondering about the AWD system in this vehicle, i know the majority of Toyota's products with the AWD (rav 4 for example) have a reactive system which only turns on once the tires slip, and is completely inactive above 40 kph (or so I'm told) is this the same system or is it actually a full time system?

I don't know about the current RX, but the '99 RX300 is full time AWD, doesn't matter what speed.