i am currently installing air lift on the front of my lambo also, from what i am reading the two black solenoids on the brass valve are for airing up and letting out air to the bags, one valve will allow air pressure from the tank go into the air bags and lift up the car, the other valve will let out air to drop the car back down. The fitting with wire on it at the air tank would be the pressure switch for the compressor, this will tell the compressor to turn on when the pressure in the air tank is too low and then will tell the compressor to turn off when its at the right air pressure, the pressure switch on the air tank should be wired to a relay that is active with the ignition on ( to prevent the compressor from running when the car is off) there is a air ride diagram in the suspension section of how one of these systems work. I hope this helps and doesnt confuse you
farmer