I already answered you on your other post. Please do not make duplicate posts to try to get faster replies.
Yes you will need to swap the entire electrical harness from the 02 to the 06, yes including the ecu from the 02.
You will need to file for VIN change as the 02 wrx has the VIN in the ECU and will be read by the emissions testing pc so you will fail due to ecu/law changes, etc. You really need to research more before you get to much more involved. There's over 2 decades of swap info.