What bass?

Do you think I should go with 2 12's or 2 10's in my 96 civic ex (will go in the trunk with a sealed box)

all depends on kind of subs you get. but assuming same kind both sizes the 12s can move more air

Yah, I wanna get a good system, but on the other hand don't wanna spend all the money. So right now I'm doing research on finding out which sub will be compatible with which amplifier, etc. etc.. I'm a little stumped on which wiring I want for the subs to the amps. For example, if I do Series Wiring (connect subs with positive of one sub to the negative of another, then use the negative of the first sub to the amp, and the positive of the second sub to the positive polarity of the amp) because it doesn't put a lot of work load on the amp, but you get more resistance. I would rather have a quieter bass than having the amp get fried, so I don't know what type of strategy to use for a sub and amp. If I could get away with using the Parallel Wiring, which puts more work load on the amp because the same voltage is going to both amps, but has less resistance... not sure.

Pry 2 Audiobahn subs and a PowerAcoustik amp.

i have a poweracoustik amp, and its better and was heaper then my other amp, and hasnt fried yet, plus im running two M.A. 12s, my amp just had two channels so it didnt any rocket science to hook it up

the way you wire your subs depends on which amp you get and how much load it can handle.
for example, if you get an amp that can handle a 1 ohm load then you can wire your subs to 1 ohm ( if they can go that low.) right now i have 2 kicker comp vr subs and a directed audio 600d amp. the amp is running at 1 ohm and works beautifully. it does not struggle at all to pound the crap out of my subs. you just need to decide either which amp you really want and then get the subs or else get the subs and then get an amp to match.

Go 12". Get some JL W6 or W7s. Then you can buy a new amp to run them. Dont settle for cheap stuff or you will have cheap sound.

Go 10's, my suggestion on what kind of speaker run would be rockford fostgate the power HX2, cost a little bit of money but itll be worth it.

speakers wired in series between each other can cause back EMF and modulate each other (cause each other to move), resulting in distortion. The problem becomes more serious as more speakers are connected in series. It's ok to wire in series between coils and between the amp, but not between speakers. Back EMF modulation is not a concern when wiring to one speaker or between the voice coils of a dual voice coil speaker because it's one cone for one speaker and for dvc speakers the coils are physically coupled on one moving mass. Therefore, they cannot possibly modulate each other because they cannot move independently.

A good experiment to show the effect of back EMF is the following: connect four speakers in series and short the positive and negative input leads of the series circuit. Push down on one cone with your hand; you will notice that the three other speakers will move in the opposite direction of the one you are pushing. Now, reconnect the speakers in parallel, short the inputs and push down on one cone. The speakers will not modulate each other because each one is shorted directly.