I use 2 Sunfire Sigs with my 3.6's. I chose them because I liked their sound and the controls they give you to help integrate. Their x/o starts at 30hz which helps blend with the Maggies starting to roll off 35hz,+ or -. Their phase control is continuously variable as opposed to a 0-180 switch, which will help with the placement. Read Sogood51's article, thanks Dave, and memorize Gmorris's reply and you will be ahead of the game. Good luck.