As the title, how do you remove the centre diff?

I'd like to turn my blob wagon 5 speed into dccd, I have the gear box from my type R out and apparently I can just remove the centre diff and fit it onto the blob box along with controller etc. Problem is I don't know how to split/ take the centre diff off, I have seen one vid on utube but it seems a bit rough and I can't see the very top of the box, they're just using a screw driver and hammer to split it but i'd like to know if there is some trick to it as I don't fancy knackering either of my gear boxes with a screw driver.

So any one done it? any tips hints or links to a better vid would be much appreciated.

 

On a WRX?

Explosives

 

cant remember if you can simply take the end plate off and withdraw the diff, or if the whole rear casing needs to come off.

have a look at this

http://ken-gilbert.com/wrx/01impreza/imp01_trans_4.pdf

is it deffo a straight swap tho, are the drop gear ratios the same?