help?

my soon-to-be growroom is about 2.5ft wide x 2.5ft long x 5ft high AT MOST. i will be using a 250w hps that has a ballast built into the reflector. http://www.specialty-lights.com/4225.html

ill have an oscillating fan and a squirrel cage fan running in the room. what CFM should i use for that space?

i know its going to stink when i start to flower my bud so what is the best way of going about taking care of that in the space i have to work with?

use a carbon filter for odor control. You can hook it up to your exhaust fan

do you have any suggestions for an exhaust fan thats not too too expensive but will get the job done and keep me out of trouble??