I have 2 AP's: a 7000 and an ACU 400 with Lecombe Schmidt (LS) hydraulic drive attached to the rudder
bell crank. Love the hydraulic and it was the only one we used during our ATL crossing last December. Super quiet for us as the pump
is located in the engine
bay.. so no noise
in aft cabin
. PLEASE specify the LS drive... the Ray ones are not very good apparently.