Tuning a port

[knocturnaldrive]

Hey
I have a rocksford fosgate 15" Z punch sub, 150rms 400 peak
i built a 2.5 cuft sealed box because the company said 2.5 for either ported or sealed.
Now i'm debating if i should port my sub so it comes into the cabin, but i don't know any of the math that goes behind it, like what diameter the port should be, or how deep it should go, or tuning, along with what side of the box the port should go.

If anyone has any tips on how to decide these things, or knows a web site that gives information on this kind of thing, that would be awesome.

Also, just a quick question, i know all these people who say ported are way louder, but than others say sealed have more punch. What do you prefer? and why?

Thanx

[Acidburn]

http://www.jlaudio.com/tutorials/
http://www.bcae1.com/spboxnew2.htm
http://www.diysubwoofers.org/
http://www.loudspeakers101.com/VentCal1.htm
those should get you started