yes
In most cases, the speakers should be able to handle more watts than the amp can deliver. Doing it the other way around will blow out the speakers.
Yes the amp can push the 2 subs. I have 2 1250 watt 12inch subs and 1 maybe 400 or 500 watt amp and the amp does fine but if you want more bass at lower levels of volume then you want to have a bigger amp. Just make sure your amp doesnt blow your subs.
4 gauge
Not if subs are rated for 2000 watts each.
A 800 watt 2 channel amp will work
YES! it won't reach it's peak, but that's also probably a good thing, cause it'll be harder to blow your sub. i prefer to buy either the exact watt match for my subs and amp, or buy the next lower watt amp from my subs
no you wont get a 5000 watt amp and u will be fine
I have 2 q power 1500 watt subs and a 3500 watt proacoustic amp and it pushes it well although not enough so im sure you need more than 2000 watt to push 3 of them.
Depends on what your willing to spend.. For two 1200 watt subs I would go with a 1200 watt amp and run both of then 600 watts ( you don't want to always run subs to full power, because the voice coil might blow or you will light your subs on fire). If your feeling brave you can run a 2000 watt amp 0_o that will annoy your neighbours, but make your car bump!
it depends on alot, alot of things. but id say to be safe a 2000 watt. but the best amp would be a sundown saz1500d
crutchfield has a wiring diagram for all kinds of configurations, check it out.