Can anyone tell me what is the best setup for the Mustang? My daughter asked for 2 12" subs and an amp for Christmas. I went and purchased Rockford Fosgate 12" subs, amp and box. Got home and the box would not even go into the trunk, and have since taken them back and bought 10" subs. Since I know nothing about stereo equipment and am the mercy of my local stereo shop...can anyone please give me some guidance as to what I should be buying.... I do not want to spend more than $600 (including installation). By the way...she has th Mach 460 now.