I assume you are buying/have bought the white GSR-X on trademe.
I have just completed a manual conversion on my FWD Sigma, but I luckily had a donor car to get all the bits I needed.
If I was to do it again I would look to use a gearbox from a SB/SC/E33A Galant. These gearboxes dont use a vacuum actuator to select 5th gear. Its all cables. Make sure to get the selector cables to suit that gearbox. For the clutch pedal I think you will need one from a manual Sigma as I dont think the Galant is the same. Pretty sure axles are the same between auto and manual.