pointless getting 2 monitors for 3d. especially if your gonna use them for gaming as your crosshair will be in the plastic between the screens. its either 1-3 or 6 for gaming.
if your just gonna use 1 for gaming then save some money and just get a standard 60hz screen for your second.
it will depend on what games you want to play. bf3 your looking at 60+ or 30+x2 fps if your using active shutter. as your creating half the fps for each eye. some games will be better than others. screen tearing will be your biggest problem though as you wont get 120fps minimum even with that setup and if you turn on adaptive vsync your gonna get definite micro stutter.