Shouldn't really need an intake fan, just the exhaust fan and some intake holes in the back wall to bring fresh air in. Dont forget the cooling fan for the light if you have that type, those lil 4in inline duct fans (home depot $20) work surprizingly well for there size and wiring consists of matching 3 wires together so very simple. As for anything else inside what kind of system is it gonna be? E&F or drip or?