At the moment I have a single 660 and only play wow, i get a steady frame rate of 120+
I have 2 questions, i am currently using a 27" monitor at 1080p, would i be able to use 2x 22" at the sides of my 27" monitor for gaming? and what sort of fps drop should i expect wehn using 3 monitors?
It will look horrible since the two on the sides are running the same resolution as the much larger middle screen, so when you turn your view everything will distort horribly as it transitions onto the smaller screens. I would not recommend it. Also, if you do go this route, preferably with monitors of the same size, your FPS will most likely be cut to 1/3 of your current framerate as it is rendering 3x as much at any given time.
You won't get more than 30 FPS at 3 monitors. And it will look terible with 22 inches in sides and 27 inches in middle. Better pick all the same size and SLI your graphis card.
By the way how many VRAM your graphics card has?