Not hard, been done.
£0 amp power supply to the ECU
control boc under one side
air tank under the other.
Weld little brackets to all 4 radius arms, drill 3 holes in the chassis at each corner and fit the ride height sensors
Relocate the front dampers ahead of the axle, unbolt and remove the spring plates, drill locating holes and fit air springs into the standard seats (albeit with extra holes in them).
ECU needs to be connected to the handbrake/park switch, speedometer, gearbox on an auto, ignition and battery. It has a 30 second delay unit but that may be shared with the electric windows.
You can clear faults with a lead sold on E-Bay, not sure if it allows you to reset the heights but I can do that for you with Rovacom.
You MUST use the correct length shockers though! and fit newish springs for the best ride.
That said, my LSE is damned crashy, if it werent that my sister's softie has the nicest ride of any RRC I've drifven i's say the EAS isn't all it's cracked up to be :-k