This is a straight forward process, removing it involved pulling the plastic bezel or trim around the radio,ac vents and pocket out. It's snug but just pulls straight out. i usually start from the top at the A/C vents and pullout and down. When it's free disconnect the 3 wiring harness on the back of it and set it aside. The radio is held in by 4 screws, 2 on each side and will pull straight out when these are removed. Finally unplug the harness in the back of the radio and reverse the whole procedure.
http://www.modifiedlife.com/2003-hyundai-sonata-car-radio-stereo-audio-wiring-diagram/
The 2003 Hyundai Sonata has 16 valves.
The 2003 Hyundai Sonata has a 5-speed manual.
The 2003 Hyundai Sonata is a gas-powered vehicle.
The 2003 Hyundai Sonata has an inline 4 engine.
The 2003 Hyundai Sonata is 15 ft. 6.9 in. (186.9 in.) long.
The curb weight of the 2003 Hyundai Sonata is 3181 lbs..
The 2003 Hyundai Sonata has double overhead cam (DOHC).
The 2003 Hyundai Sonata runs on regular unleaded.
The 2003 Hyundai Sonata's turning circle is 34.4 ft..
The height of the 2003 Hyundai Sonata is 4 ft. 8 in. (56 in.).
You cannot use the 2004 Hyundai Sonata body parts on a 2003 Hyundai Sonata.