I have it wired parallel running it at 2ohm though a 500rms exile amp and it just cant keep up. I have all my settings at half on my amp and the sub just sounds cheap(really solid at some low tones and not so **** hot at others) . I'm really not suprised though seeing as it only weighs a wopping 8lbs. I would just buy another one and add it to the system, however my amp is not 1ohm stable. I would suggest looking at the higher rated phantom series.
Cheers!

One speaker. Dual (2) voice coils rated @ 4 ohms each. Wired in parallel, the amp will see a 2 ohm load, thus deliver more power. Basic electronics.