My 3" system needed a little and I had it but still came in way under those other guys. Here's what it sounds like on a semi-built 440.
http://www.youtube.com/watch?v=OPPjBNwdHfA outside car
http://www.youtube.com/watch?v=XoCaHhiqShI&feature=related in car

[IMG]http://i66.tinypic.com/pui5j.jpg[/IMG]
Coming soon!!!!