3x3x6 space. 400w or 600w hps?

I am going for maximum growth and was plannin on using a 400W hps for flowering but now I'm wondering if a 600W would be better or just overkill?
Ventilation will be done with a 6" inline fan hooked to a filter.
Any ideas or name brand lights I should get?

go with the 400. the 6 is way to hot for the space, happy growing bro.

I haven't started yet, but I have mounted my 400 in a 3 x 3 x 7.5 closet......I left it on over night, and it got HOT!!! A 600 would definitely be over kill. hey koi, keep in touch man, maybe we can help each other out since we have the same size closet...i'm still trying to figure out the best setup for mine...would love to get a perpetual harvest going in there!

i have a space around 3x4x3, i run a 250 and 400 with 1 x 4 inch inline and 1 x 5 inch inline, heat ok at mo..........

do u meen feet when u say 3x3x6 ? or is that metres ?

no way 6 metres hi, he means feet

Yes I mean feet.
I have used a 400W in the past in an even bigger area and it worked ok.
But if you calculate the lumen output with this setting in my new room its around 6000 per square feet.
I was reading Ideal lighting.would be 7000-10000 lumen per Square foot.
I'll document my grow when I get started and keep you posted.

im growing with 81000 lumens in a 3x4x3 with good effect, 5000 lumens a foot is ok i believe