its an I4 btw
but i think the motor in the 99 was an F22 while the 03 accord is a K24, so if you wanna do this swap, you will need the whole motor, tranny, ecu, axles, prolly hubs, wiring changes, etc etc to get it to work.
imo itd be easier to drop the h22 in or maybe even the v6 from that year.