I know that Brian at Rythmik typically recommends down firing subs only on solid surfaces (like carpet on concrete).
My sub will be sitting on carpet, not with concrete but with plywood sub-floor...looks like front-firing might be the correct recipe for me. One of the reasons I was favoring down-firing was to lazily avoid building a grill... my 2-month old grandson will be mobile soon enough and speaker drivers are entirely too interesting for curious minds and fingers to avoid

Corndog, that is a great-looking sub...I'm sure it is rock-solid! I also share the sentiment it would best be finished stained/sealed to preserve the laminated look.
Plund