[pete3799]

Originally Posted by Ayles

Once you have tried everything with no success you can carefully cut the nuts off with a dremel and replace the line or use elephant racings nut kit. I had to cut both nuts on the engine side of the thermostat. I fought with them for a couple weeks before cutting. They just wouldn't budge.

http://forums.pelicanparts.com/porsche-911-technical-forum/765568-oil-lines.html

^this.
If they won't break loose by hand.......cut the nuts. Don't use a cheater pipe as you'll likely peel the threads off the thermostat $$$$.
Mine wouldn't budge either. Slice the nut carefully so as not to get into the threads.
If you nick them a little you'll still be alright as the hose seals on the end not on the threads.