I don\'t see why MGS2 wouldn\'t support pseudo surround at least. MGS on the PSX supported my setup, even if it wasn\'t real surround sound. I don\'t see what the big deal with DTS 5.1 is anyhow, being that the average joe doesn\'t have a stereo, let alone a DTS 5.1 setup.
EDIT: I currently have a DTS 5.1 decoder, and I love it. In movies that support it, you can hear all sorts of things going on behind you. It\'s really quite amazing if you\'ve never heard it before.