The JL CR1 is $3k. Nelson pass makes the b5 and the b4 which are $1500
http://www.lowther-america.com/First...mplifiers.html
but he also makes the XVR-1
http://www.stereotimes.com/amp021513.shtml
If my sub has a built in low pass filter, would the maggie 3.7i benefit from such a device?