Let me start by saying, in reference to your signature, they are made by the company American Bass, but yea you guessed it Made in China lol.
That being said, the XFL's come in 10's 12's and 15's (dual 4) and you can get the 10's and 12's in dual 2 as well. It just happens they are the lowest line AB offers with a dual 2 coil configuration.
I have been testing mine for about 3 months now. I also bought a brand new one that I will be doing a break in comparison too (how much louder do they get once broken in).
Also, on purpose, I have been feeding mine a fully clipped 500 watt signal to test the affects of clipping at well under the RMS rating of the sub. So far, it gets a little warm, but I have yet to smell voice coils and the impedance has not changed.
They get pretty loud off ~500 watts and seem to have good output even below port tuning. The suspension is very stiff of course.
I will also be doing a direct comparison between an XFL 1222 and a FI Audio SSD 12.
I will make some posts with my test results if your interested.