Grow Tent Wattage Question

Hi Im planning my first grow. Im planning on using a 96"x 48" with 78 " oh height..

With those measurements said, i was thinking a 1000 watt and 4 plants using the scrog method.

really open to suggestions and need advice on grow medium. I wanna make a organic mix.

and would 1000 be too much or should i get a 600 watt

1x1000 watt should be fine as long as you can cool it.
But with that size tent if I wasn't using a1000 I would try to fit 2x600 watts in there.

Sweet thanks guys, whats the general CFM i will need too if i plan on a 1000watt.
This is the light
http://www.amazon.com/Virtual-Sun-VS1000MS-Magnetic-Ballast/dp/B004DEBD0A/ref=sr_1_1?ie=UTF8&qid=1316070362&sr=8-1

For exhaust im so lost... i understand the exhaust for the light and the intake of fresh air for the light (hence the 2 BIG holes on each side..) but where does the Carbon filter go? and do i need more exhausts/intake???

you guys would be sooo helpful if i could just get a sliver of advice!

Thanks!