That looks ok for growing 2 small plants, is there a way to adjust the lights to keep them right above the plants? The thing with cfls is that you need the plants within 2 inches to really get an effect from them. If the lights are too far away the plants will grow tall and spindly, stretching to get near the light, then you soon run out of space.
The fans, I'll assume one is an intake and the other exhaust? You'd be better off placing them next to each other, both exhausting air out, and a passive intake at the opposite end. If you have two fans at say, 50cfm, and use one as an intake and the other as exhaust, you are moving 50 cubic feet of air per minute through the box. If both are exhausts, and air is free to flow in, then you are moving 100cfm.
Don't want to move that much air? Just use one as an exhaust and take the other out, it's only wasting electricity by moving the same amount of air that would flow in of it's own accord.
Are those the pots the plants will finish in? If the plants fill the box (and I suspect they will) then they will need watering often, 1-3 times a day depending on strain and environmental conditions imo. They will grow ok, so long as you water them when they need it and not too soon. There is a much smaller margin for error when growing in small pots, I just wanted to be sure you were aware of this as this sounds like your first grow.