Well just a solution I need to share with you.

If you have a nemesis and need to work on the center diff (installing reverse or other mod) and having trouble with the impossibly tight screws follow my story.

I tried to open the screws using a normal allen wrench... NO WAY
I put a lighter under the diff... NO WAY

All i did was screw up the screw heads, and even twisted an allan wrench.

Put the whole and complete center in the oven (just your general kitchen oven) @ 200 degrees celcius for 20 minutes -> easy unscrewing... YAH

I hope people read this first before they screw up their center diff screws. Be prepared for some diff grease to leak out though, and use a towel (several layers) when handling the hot diff.

Cheers,

Crus