The guys at kicker said to tune to 39hz for 4x12" CVR's in a 9sq foot box. I don't see many people tuning much higher than 35hz though. So should I take their word for it and tune for 39hz or drop down to 35?

This is my first ported box so, I'm somewhat at a loss.

I'd much prefer the 35Hz tuning over the 39.

Depends on your goals. 39hz will have more output, but I personally couldn't handle listening to it.

which is exactly what kicker is aiming for, output that is.

35hz will yeild a much better overall sound, while not really causing you much loss in over all output. and depending upon vehicle, might not cause any loss.

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

It's actually going in a extended cab ford ranger haha

Should I still go with the 12sq inches of port opening per sq foot of box? How do I figure out the length of the port if I tuned to 35hz?

Sorry for all the newb questions.