@ jdraup:
Hard to say if you have a DME 7.8, or a 7.2. but i think will be a 7.8. There are some differences between US market and EU market. And to be honest I'm more into EU specs and have to do a little more research about US specs.
I think your car doesn't have is a seperate fuel filter that can be changed seperately. This is an integrated part of the the fuel pump since Mj 2002.
I'm with you when it it comes to original Porsche spare part prices. In general they are you relabeled and have the same quality specs. So i would go with Bosch or other quality replacement parts instead of original Porsche parts like Bosch, BERU etc.
If you remove the oil cap and the engine idle bounces a little bit and is rough - that's normal, because the vacuum system has a so to say leak while the oil cap is removed.
Maybe it's best to observe the error codes for some miles and clear it when it comes again. If it shows up too often i would change the 2nd o2 sensor. Because it's an error at idle revs i don't think that will harm anything enginewise. So it's more or less an emission problem. Nothing that really can harm the engine. Nothing that should be written on your gravestone, or from what you should get any grey hairs.
General sensor values seems to be OK to me. Mine's are little different - have a EU car and a S version.
@JFP in PA:
Absolutely with you only to change parts that are broken. But in the case of o2 sensors it's really better to change pairwise, because the DME can generate errors even if the old o2 sensor is working within given specs.
Regards