My 182 has two Garmin 430Ws, STEC 60-2 autopilot with auto trim, and Aspen PFD Pro with GPSS. I fly transition RNAV approaches with the 60-2 in HDG and ALT modes and the Aspen in GPSS. When established on final I switch the 60-2 to NAV mode well outside the FAF to arm glideslope capture...