stick with cfl's man until your ready, or have a better space. look into ScrOg, you'll be able to up your yield majorly in that small space. I would highly suggest going HID maybe find a new grow space? HID is worth is for sure man...I'll never go back, cfls have their place, but HID is a place above. cut your teeth with those cfls if you can get like 6 or 8 in there you could grow some nice buds. And with HPS your area would be so small I would suggest just having a strong exhaust fan so that it got the heat from the light and the grow area, a cooltube in there would be unnecessary. just a small batwing would be the most space effective and then just have a good strong fan like even 300cfm (not super powerful) if you were in that range I think you would be totally exchanging the air in there each second, that would keep a 150 as cool as it needs to be.