Hi, I replaced mone on my RX300, it has one on the drivers side rear. Basically its a 2 miniute job, use a 10mm spanner on 2 nuts and unplug the wire.
Didn't even have to jack the car up, also didnt have to calibrate it (car has since passed its mot)...
I agree that the part is a big rip-off..
I think its the same part, my headlighets were bobbing up and down at traffic lights, it was like being at a disco. Fault turned out to be a seal that broke on the ride height sensor, dirt had got in and corroded the internal PCB.
Regards
Paul