Do not plug the ports, it can only hurt u. Adding box stuffing will make the speakers think they are in a bigger box and help eliminate the backwaves coming from the speaker, therefore making the subs go lower, however this will only work to a point and then you will be hurting yourself

Thanks for all the help. I think i will pass on the poly fill. I dont know much about that kind of stuff, and they sound fine as it is. Disconnecting the tweeters was well worth it. Thanks again everyone!

Plugging a ported box will not hurt anything, but it will change the way your subs sound, they will hit harder but wont sound as low. also there will be much less phase shift, which helps with the crossover to the main speakers. Ported is louder, but if the box isnt built exactly to specs with the right amout of volume and polyfill, you may get wierd humps in the frequency response. Plugging the ports to hear the difference would be a good comparison. Jachin is right, polyfill can help in tuning your box.
footballplayer: Can you give me the inside dimensions of your box? also the port length and diameter? if so I have a program that can give a general idea of how your ported box wil respond. bottom line, as long as you are happy thats all that matters

Ported boxes are always larger, therefore if you plug that port, you will go lower, and have a flatter response curve, but it wont be as loud, thats the whole point of a ported box, is volume

some people prefer the boomies sound of a ported box, it depends onthe type of music.For maximum volume bandpass is the way to go, but hard to build and narrow pass band. Im just saying that pluggin the port(*) will give you a different sound and its good to be able to do an A B comparison.

not likely there is 14.4v at the battery but the resistance of the wires brings down the voltage. and the more accessories the less power you have.

it all depends on what your voltmeter says. Your battery will be getting whatever your alternator decides to putout on cold days with a sucky battery my alt has put out 16.3 volts (between charging the battery [it was nearly dead] and running the stereo and the defroster it was puting out a stout 120 amps (yes my alt can do that, check sig)), but usually averages about 13.8-14. And if you use the right gauge wire resistance in the power wire should be negligable.

And theoretically if you have a correctly working alternator, isnt it supposed to stay at mostly constant voltage while varying amperage for the accesories?

the more accessories that you have the more load that you put on the alt and the battery. that is why the car may not be running at 12-14.4