I heard two of the RFL's built into a wall in a ford probe with about 2500w each going to them, and i can honestly say it was some of the most distorted awful NOISE (not music, mind you) i've ever heard in my life. It sounded like the engine brake of a mack truck, only louder. When i first saw the sub, i was really impressed with the way it looked, and all the juice he had hooked to it, but after it burped a couple times, i was left with the question "why in hell would you pay so much for that?" He also told me that it had a problem with overheating and melting voice coils if it was played for more than a few minutes at at time, and that's why they include a rebuild kit. he used both of his replacement coils within the first two weeks of owning the subs. i don't know much about the MMATS subs, but from reading IASCA results, it has to be a pretty decent product.