Power is stupid cheap now. The 3 main options are chinese, like the CAB, Korean like Sundown, DC, DD or Brazillian, like Taramaps and Banda. All topologies differ. I prefer and run Korean because i compete and Korean withstands the most abuse (ie 0.25 burps at 11v).
The motorforce of subs now days is crazy. People with 1 12 are as loud as people who had 4 15s walled in the 90s.
Im running 2 12s on a korean 3k and do 151 legal.
Zapco still makes good shit, but their lower lines got outsourced to china.
Imo Sundown is the best all around company.