Definitely improved my MET pro. Not so much loud but more balanced. The sub comes with one extra lead. One with more bass and one with less bass. Everything's wired and ready to go. takes 15 minutes. If you could build the wiring yourself I bet you can source everything for 1/3-1/2 of the money. But that's if you have the tools and skill.
Basically while it's nothing like an "OMG Home theatre type of awe" it's definitely a great although somewhat subtle improvement.
Edit: I got the basic 2 woofers and sub setup. not the Whole shebang! that's why it's subtle but you hear all of the game much better. sub isn't too overwhelming going this way.