You're going to have to be careful using a EP2500 for this. The sub will reach Xmax with 250 watts. You will also need a high pass filter (rumble filter) at 14 hz to protect the subs from over excursion at the lower frequencies. Consider the Reckhorn B1 or E.D. eQ.2, about $100.
With room gain you can expect 110-112 db down to 16 hz. For porting you can use a 6 inch diameter tube 23 inches long or two Parts Express 4 inch flared ports 22 inches long.
Depending on how wide and tall you want your tubes, here are the measurements for a 20 inch diameter tube....
a 22 inch diameter tube....
and a 24 inch diameter tube. Your choice.
Note the sub used in the program is the Dayton Reference, it was used for mounting depth purposes only.