OK, I had some time, so here is the info...
Front and rear Speakers : Focal 130 CVX Polyglass 5.25"
(Scoche SA68 speaker adapters)
Head Unit: Pioneer AVIC-X940BT In-Dash Navigation AV Receiver Amazon.com: Pioneer AVIC-X940BT In-Dash Navigation AV Receiver with 6.1" WVGA Touchscreen and Built-In Bluetooth: Car Electronics
Dash Kit/Harness Metra 99-5823CH Metra Part # 99-5823CH | Ford Mustang Dash kit | Metra Online
I had an audio shop install everything for me(not my thing), they had the wiring needed for the job. I really like the Metra, still retains all the controls of the stock unit, and you can still keep the steering wheel controls. Total cost, including the parts and install was about $1500. I couldn't be more pleased. Oh and I also have a 12" Kenwood sub in the trunk with two Kicker amps, one for the Focals and one for the sub. I consider myself an audiophile, in car and home theater, and these Focals are amazing.
On a side note, the Metra can be expensive online, If you have a local shop, check with them, they might work with you, mine got it for me for just a little over cost.
Anything I can help with, feel free!