Nick, get a Crown XLS series amp.......build one or more of these. It's not a joke and the combo of the Crown and a few of these, I only use one, will slay pretty much anything. I have offered to give one to anyone who could find it by listening. No one has. It hides in a corner behind a cabinet 5 feet from the couch. it is impossible to locate.
Bruce measured it and you can read his results. While it makes no sense, it is superb by any standard..... it is the "F**king Fantastic Redneck Subwoofer Mark 4:20 Inspired" The "Mark 4:20" can be a reference to the King James version of the Bible or Cheech and Chong, you decide!
The thing is not a joke. Follow directions EXACTLY.
ps.......doing my best to advance the state of DIY into the 20th century