Originally Posted by smokey847
So this basically just sends more bass to the subwoofers. I reached behind the seat when bassy music was playing and felt almost no bass coming from the rear speakers...

Exactly, It cuts back the bass in the doors and allows you to turn up the bass and drive the sub woofers behind the seats.
The door speakers come alive with midrange as well.
It is a great mod at any volume. I used a set of 330uf capcitors.