Joined: Dec 2007
Location: New Smyrna Beach
I had the same issue however the reason why people are having issues with aftermarket radios is they are not buying the correct wiring harness to install an aftermarket radio. The stock unit has factory installed amplifiers. Aftermarket radios have spots on the back of the unit called rca inputs. These inputs need a rca cables plugged into the cd player for the subwoofers to work correctly. The wiring harness can be purchased from a car audio supplier. It isnt that hard to install it just do it correctly.
2003 Mustang GT Convertible 5 speed - Mostly stock 4.6... 455 rwhp and 573 ft/lbs torque. (SOLD due to divorce)
Currently working on Coyote Swap of a 2004 GT