GT Kruzr is right, for the '04s the upgrade is just the PCM. The higher flow fuel injectors come standard on the '04s, which is why they have the extra 5HP over the '03s.
Since Mopar redid their website it's a bit tricky to find the PDF file with the install instructions, but I happen to have a copy
HERE You probably want to right click the link and choose "Save as" to download it.
These instructions are for the '03 so they show the fuel injector swap, but it has drawings of the PCM and its location on the firewall. The last page outlines the auto tranny quick learn procedure. You will recieve instructions with the PCM that are specific to the '04 so you shouldn't have to print these out.