I recently got a chance to play with a Power Acoustik MOFO 12 and a Precision Power PC.12. I ran WT3 on them before installing them into their repective cars. I did not have both on hand at the same time but made some quick comparisons. I saw that both motor structures were using the same magnet, had the same Theile Small peremeters and many of the specs on the Epsilon product sheets matched up. Funny thing is would have never put these two in the same category but come to find out they are the same sub.
If you are interested in the 200 ish dollar PPI PC.12, save yourself some coin and buy the MOFO 12. Its the same subwoofer with inflated specs.
Wish I could get two of these together to get some better data but just found it to be interesting since PPI is marketed as a high end sub and the Power Acoustik is entry level. PPI is going the way of General Motors and using the old platform sharing trick on subwoofers.