funny since that torres box calculator came out everyone thinks they are a pro and think they can design a box all the sudden. there is more than just plugging in numbers to building a great/correct box. every vehicle and every subwoofer is different and it also depends on how much power you plan on using so there is many factors that make up how u wanna design something.
honestly the fad on this forum and most others is huge box huge port to drop low. its not neccessary but its a way to make it work. as far as port size goes it depends on your application. you can get away with a smaller port if you are unable to get the port length. port length plays a roll on wave travel and all that jazz that torres fails to calculate out