Use the correct NAV source (VOR1/VOR2/FMS, as per NAV SRC selection)
Turn anticipation (not perfect, but does the job)
Restructured and retuned vertical controllers
Proper SPD modes: first push selects CLB / DES mode (CLB: IAS climb but lock V/S to >= 0; DES: IAS descent but lock V/S to <= 0), second push selects "dumb" IAS hold.
Various improvements to the autoflight system: