Audio Systems: which sub, watt rms, mono block

Question
I am getting sponsored by Optionaudio.com.au
I have been offered a 500Wrms mono block AMP 2 ohm.
Choice is between Street series 12" 500Wrms Sub DVC 4 ohm (wired in parallel = 2 ohm)
or
Pro series 12" 800Wrms Sub DVC 4 ohm (wired in parallel = 2 ohm)

Which is better if I need to stick with the 500Wrms AMP?

Which subwoofer would sound best?

Answer
The Street Series 500 watt RMS is a closer match. However, look at the sensitivity of each sub. Which ever has the higher dB is more efficient. This means it takes less power on one sub to push the same power on an another with a lesser dB rating.

dB ratings go as follows:

The sensitivity of a sub is determined by how many dBs are pushed from a sub with 1 watt of power at 1 meter. You get a 3db increase in volume for every doubling of power.

If a sub has a 91dB sensitivity then..

1 watt = 91dB
2 watts = 94dB
4 watts = 97dB
8 watts = 100dB
16 watts = 103dB
and so on....

Keep in mind other factors inhibit this dB calculation so the end result won't follow this pattern.

I would guess you could push between 110 - 115dB total with that sub.