If your HU says ford on it then it's not a premium unit. Ford just buys Sony's leftover parts and glues them together with monkey crap. Then they shove a premium sticker on it. I would suggest you get a new deck before you do anything else to your car. The sound quality will skyrocket with even an Alpine CDM-7854 (around $300) and a more expensive deck, the sound qualiity goes even higher. I personally prefer quality sound over bass.
The Honkeytonk
Monkey