Yea...Well what do you want to know:
1. The smaller the port length, the higher the tunning for a given port area.
2. When figguring out your NET box volume(the real volume minus the port displacement(port takinup space and sub)) you should minus that displacement of the port(subwoofer too) and re calculate your gross box volume(volume of inside box reguarless of inside stuff).
BCAE.com has a calulator for that..but i dnt recc it...I'ts just there if u want to use.