im currently running 2 12 inch orion h2s with a wcc 5000 watts max amp
if I added another amp and 2 subs would that make me a whole lot louder
and is it a good idea ?

 

Yes with the correct enclosure it will be a lot louder.

It's up to you if it's a good idea or not but you'll need enough space to fit the enclosure and an electrical system strong enough to handle the 600a+ that two of those amps will pull.
An easier way to get louder might be to swap out the 12's for a pair of 15's instead.

 

I would like to go with another 2 12s eventually have some kind of custom work done in the trunk with all 4 subs

theres a comp coming up in august so I was looking to add another 2 subs and another amp to make it alot louder for the comp

I have all directed audio 0 gauge wire

 

Back up the bus. Does the trunk actually have room to properly fit all 4 subs and the proper box for them? What kind of box are the subs in now. It may just be a change to your existing box that you require.

 

ive got an 02 civic coupe

their in a slot ported duol 12 box so no I cant customize the box but I was thinking for that comp of just putting another box with 2 12s in the back seat with the other amp

 

hmmmmm.....the sound of crickets chirping whilst everyone considers their response.....

 

wrong in too many ways to name

 

im gonna need a custom box made for the trunk I know

 

And what is the specs on the enclosure they're in now?

 

bass slammer duol 12s box

http://www.bassslammer.com/products/hybrid/W112.120HG.pdf