power available through parallel wiring
 

i understand that wiring in parallel mathematically lowers impedance but what happens to the power of the driver? do they still stay the same just at a lower impedance or decrease/increase at the lower impedance

The driver is the resistance , it determins the load your sub won't see a difference if connected to other coils except for the power difference power is determined by the amp, when the resistance is decreased by adding woofers think of it as giveing the amp more places for it to push power there for having more to give in the right circomstance

shoulda been more clear, not a sub setup but component, but i guess it really doesn't matter, coil is a coil :)

but i might be a bit daft i get but don't get your explanation, please re-explain it or if you got a mathematical equation for power

Power = Voltage^2 / Resistance

This is why when you halve the resistance by wiring in parallel the power output of the amplifier doubles - assuming the voltage does not drop due to power supply limitations.
If you had one speaker hooked up to the amp and then connected a second identical speaker, the first one would operate the same as before. It is the amplifier that 'notices' the change in operation.

Reality is the power supply will sag a bit as impedance goes down so you don't get perfect power doubling, but for our purposes it's close enough.