HobbyKing plug & play Aircraft Engine Sound Module System(SMS) $40 Runs on 3-4S battery, Connects to the models ESC and outputs an engine sound based on throttle setting through a speaker (supplied).
ESC Dlux HV 120A 6-12S No BEC $150
ESC Dlux 100A 2-6S SBec $80
Dr Madthrust machine gun sound sim module(with speaker) and dual flashing LEDs(gun flash) Module. Needs a power switch module to turn off and on(not incl) $15 for both.
ASSAN Door and Gear sequencer Input: 1 servo Channel. Output: 3 Channels (retracts and 2 x doors) set up via 4 buttons on the reverse of the sequencer which also features a large, easy to read LED display $15