you need the atessa conrol valve and pump plus a standalone controller to map the centre diff. Remember they are 100% rwd until you pressurise the centre clutch pack and split the drive to the front. I use a control unit called MAPDCCD as used on a Subaru. Works brilliant. So much so im keeping it to control the centre diff going back in. I'm just changing the actual gearbox.

What you have to consider is why you are doing the conversion and what do you want from it.
If its a transmission that will handle 500hp + no problem without breaking then thats the reason. If you want split drive then you need the active centre.