Hey Bro..
I have my roof rack converted to a light bar front and back, they are 4 across the front and measure about 6.5"X3.75". I also have 2 of them at the back facing the rear, it looks great the lights are 55w halogen and work very well for the price I paid, I have $75 CND invested including wires and switches, my brother who owns a stereo shop installed them and I have no problems at all, just to let you know though depends on how you mount them, once mine were in, the roof rack could not be adjusted, so pick you location carefully as once they are mounted and wired in, thats it...
GQ