MDF grow box

I'm finally starting to put together plans for my grow box. I've got some lowryder #2 and LA Woman I'm going to be growing (at different times).

I use to build speaker boxes professionally for car audio competitions and the wood standard is MDF (medium density fiberboard). Unfortunately it's a pretty porous wood.

Does anyone have experience using this wood? I'm afraid, being so porous, that I'll have an odor problem? I'll be using 4" flexible piping, a squirrel cage fan, and an inline carbon filter.

Here are the two ideas I've been kicking around in my head. The point it to make it look like a tool closet that I had built a few years back. Completely light sealed (hopefully silent). Something I can keep locked and if ever questioned by my landlord on a inspection (she hasn't even called once since I moved into the house) I can just tell her that I have $10,000 worth of tools I don't want stolen.

I left off the door, but the door will go from the bottom to the top, so you can't tell there is a top chamber. just looks like a large wardrobe closet

Idea 1
http://i40.tinypic.com/inbyvn.png

Idea 2
http://i41.tinypic.com/292mqu0.png