I think MTX subs sound like ****ing ass. I've heard 4000's 6000's and 8000's, and all sounded extremely muddy and nasty. I have a ported L7 and kicker 600.1, and I like it pretty alright. It's a little too muddy for me, but that is because I listen to lots of rock/metal. If I put in some rap or techno, or something of that nature, it just sounds beautiful. Also, if your into SPL figures, it hit 138.8DB in a mecca competetion.