The important factor, how and can you move the air? Those 105's give off alittle bit, but nothing like a 400 watt hps/mh... You have a lot of choices a head of you. If you can move air, like say through the ceiling, intake and exhaust. A 400 watt would be killer! You can cool tube the light etc. You have to make sure your space can handle it... I hate seeing Help threads because somebody put a 400 watt, 600 watt etc in a closet and it's 105 up in that mug.... Cfl's can get a respectable grow, I dont believe to the extent of a HID light used properly in a controlled enviroment though.
Just my 2 cents.