Not trying to flame, but your original post states that your changing from det to de, but this post you state it originally had a de?
How many times has the motor been changed?
And if your a P - plater why buy a turbo car in the first place?
Anyways, good luck with your project and IMO you should leave the box attached to the motor, pull out shifter with circlip removers or long nose pliers, remove tail shaft (4 bolts diff, 4 bolts at box and two I think for centre bearing), slide tailshaft out from diff side first then out of box, support the box with trolley jack, remove box mount then think about the rest.
Theres a really good guide on here for r32 rb25det conversion, not exactly the same thing but should be helpful none the less, I think its by predator.