I just traded in my 15 fusion TI for an Edge 17 TI. Both Sony systems.
Here's what I did on the Fusion: I installed, ever so lightly, a 200 watt stereo Kenwood amp
in the trunk, mono tied for a full 200 watt output. I fed the audio signal into an 8 ohm Pioneer
12 inch sub in an enclosure I purpose bought together. I measured the 12 volt's input to the
amp with an in line digital multimeter. She was amazingly only drawing about 5 amps at a
very satisfactory setting. Inputs on this amp are twin, i.e.; high or low level. So i simply
tapped the rear package shelf twin subs with their high level outs to the amp in's.
I built a simply switch box with a red LED when 'on', and utilized the front lower dash
12 volt power point to plug in for power. The PP had a 20 amp fuse and stays on one hour
after the car is shut off. (Yes, once in a while i did forget to turn it off.)
When the weather breaks warmer, i plan to do the same on my new Edge.
I will simply tap the rear sub for the HL signal to the input of the amp.
Whether stereo or not, one channel was enough to satisfy the 'LOWER END"!
Wish me luck...