You don't need to replace the flame trap. Just remove it and forget it. Volvo put out several TSBs about the the problem. Flame trap tends to get clogged with oil deposits and most mechanics don't even know it exists.
Take out the white flame trap, reassemble the hoses, done. You can add a catch can if you wish. It certainly helps keep the intake manifold clean. I had one on my 240 for a while but I don't on our 960 or 850.