-Strictly speaker-ing, the math works like this. Let's start with the basics and compare what a doubling of the volume to the ear look like in decibels (either efficiency or relative to a doubling of wattage, 3 db is 3 db). At 1 watt 1 meter it takes roughly 9-10 db for the ear to perceive a doubling of the volume (SPL). Starting with wattage, here is what it takes to double the volume at the ear using wattage. Starting with any driver and a 500 watt amplifier.
500 to 1000 watts - +3 db increase in output (33% louder)
1000 to 2000 watts - another +3 db increase in output (plus 6 db over 500 watts and 66% louder)
2000 to 4000 watts - another +3 db increase in output and roughly 99% louder than 500 watts or a doubling of the volume to the ear.
Using a single driver for comparison (keeps it simple though the math applies in multiples too) a woofer that is 9-10 db more efficient and all other things (like cone size, xmech/xmax, etc) being the same, that driver will be twice as loud at the same input as the one that is 9-10 db less efficient. So, while this true, if the less efficient driver is less by that 9-10 db and could take 8 times the power, it can be as loud as the super efficient driver too.
Using the math, let's give the Pioneers their 500 watts and their 10 db higher efficiency compared to the other sub in the list. Since we know the other driver is going to get 33% louder at 1000 watts that it will at 500, that still makes the Pioneer sub about 66% louder at 500 watts than the Pride will be at 1000 watts/86 db.
Again, eliminating many of the variables that can play a part, strictly speaking, the Pride (if it could handle it) would need about 4000 watts of input to equal the Pioneer at 500 watts. I know it seems cray, but the math (and the physics) don't lie!
Just build a better box and use the Pioneers.