HELP N3WB GROWER on first growbox

im planning a grow, i havnt been looking in to it long at the moment but i have a fairly big wardrobe (4ft x 2ft x 6ft) that im planning to make a box out of for 4-5 plants, im thinking of using 2 HPS e40 400watt grow light bulbs, and a home made carbon filter i know i need more ventilation like an intake fan (which i need to find a cheap solution to) i need help on any tips on ventilation (how much will i need?) any tips on lighting? just cheap links? or anything really?
and im tryining to keep it as low cost as possible please
these are the bulbs im planning to use

http://www.amazon.co.uk/gp/offer-listing/B002VH1TNM/sr=/qid=/ref=olp_tab_new?ie=UTF8&coliid=&me=&qid=&sr=&seller=&colid=&condition=new

I'm pretty new to this too but I would say that that is not enough room for 4-5 full grown pants. The dimensions for my grow tent are 3x3x6 and my two plants are getting a little cramped and over heated. The 2 bulbs might be a little over kill as well as make your grow area unnecessarily hot. I used one 400 watt MH bulb for vegging and a 400 watt HPS bulb for flowering. Using only one should save you a lot of money on materials and on electricity as well.

thanks for the input i was beginning to think 4-5 plants would be abit cramped, i will probably still get the 2 and just use one for now to see, what fans have you been using for ventilation, im not sure what to go for really :S

and do you think 3 plants would grow alright in this space?

I have a 4" rotary fan I got from hugeharvest.com. If you ScrOG or tie them down maybe but you should have a good ventilation system set up as well as make sure you keep the light far enough away from the tops as not to burn them.

yerr, i know i need to keep the lights away from the plants so i dont burn them, im still trying to figure out the cheapest yet most effective way to ventilate my growdrobe, ive been thinking bathroom ventilation fans, reckon theese will keep it cool enough?

i dont see why not

I have a 2x5x6 cab. i have a 120cfm fan exaust up top& 4" holeat bottom where it pulls in air.passive intake/exuast.its workin for me.

Oh yah- ive got 2 flowering& mite be able to fit 3.itl be hard tho.6wks flowr&colas fallen over!havting to tie'em up