Just checked the Parts catalogue, and the only Engine section differences between 02 and 03 are the cruise control and the fuel pump. The mounts are the same.
However, the ECMs are different, and so are the crank angle sensors. There are some different wiring harnesses, but these are identified by VIN, not model year.
In the Emission Control section (where all the sensors are), there is one difference - the air cut-off valve and securing bolt are different. Whether they matter as regards the ECM
? Maybe use your old one.
I'd say you'd be fine if you keep the 02 cruise (if you have it), and maybe you might need to swap the crank angle sensors (but I'd be surprised). Keep your harness and ECM.