Well those compression numbers look really good! The fact that adding oil raised the compression slightly, but relatively the same as before you added the oil - shows that the rings are doing their job. I would not suspect any compression or valve sealing issues at this point - at least they wouldn't be at the top of the list.
Did anyone take a look at the throttle body? Pretty much all the "expensive" bits were changed first. I would suspect that the throttle body is a little dirty, possibly the IAC valve on the throttle body is sticking on you. That allows the ECM to bump up the idle speed when the load demands it as well as allow enough air to bypass a closed throttle plate to allow a smooth idle.
Vacuum leaks, bad ECT switch, faulty new parts or something get screwed up during the installation of new parts. Have you tried running a tank of premium octane, just to see if the car responds differently. If you get pinging and detonation on regular gasoline due to excessive carbon buildup - the engine will generally run markedly better on higher octane (also generally see an increase in MPG as well). At least, it will tell you if there is excessive deposits to worry about (have to use a borescope or pull the head off to verify otherwise).
P0303 and P0304 indicate a possible lead - that maybe the igniter on #3 or #4 could be loosing spark. Try swapping #3 with number #2 and see if the misfire follows the coil pack or stays with the cylinder. Due the same thing with #4 and swap with the #2 igniter or #1. I like to swap only one at a time to note any change - doing too many changes at once could complicate the diagnosis.
