i have a pioneer KEH-P8600R head unit a pioneer 7600DSP a pair of pioneerTS-A6999 6x9 in the back dash a pair of pioneer 6.5 2way in the front door and a pair of pioneer 4.5 2way in the front dash. Using pioneer CDX-P1250 12disc changer. On the 6x9s and 6.5s using pioneer GM-X904 4 channnel amp.Running the 4.5s of the head unit and using 2 xtants 12" subs and running a MTX 81000D to them in a seal box with 1.1cubit for each woofer and has the gain to max ,feq to 40 and equ to about half.To me and almost every one who heard it it sounds real nice . Just want to know what others think?? Almost forgot i'am using a bass control switch to control my bass from the inside.