Hey there I have done this conversion :)
You will need 4 speed auto cooler lines they are of different size to the 3 speed, I would also suggest a trans cooler be fitted.
You can integrate the wiring to your existing harness, or get an EA 30th anniversary complete wiring loom and install that, integration was pretty easy, I had to re-wire the plug from the gearbox to the existing loom in order to get the pins correct, send me an email email@example.com
if you would like an excel spreadsheet with some wiring detail.
Cross memeber you need to make up a couple of small extender brackets to get the 4 speed to bolt up as the mount points are just all wrong.
The exhaust bracket at the gearbox will also not line up, you will need to goto an exhaust shop when finished for a re-alignment.
Otherwise the tail shaft etc all fits no problems, and the gearbox does bolt up to the engine without drama.