First, the answer to my own question: who cares?

Second, my question(s):

My engine idles fine, unless the a/c is on, then it dips as low as 600-650 rpm. It has never died from this, but just shakes and rumbles more. I suspect this might have something to do with the a/c compressor, which creaks and groans a little when engaged, but in any case the a/c blows ice cold (converted to 134a a year ago, by the way). In sum: idle fine, a/c fine, idle not fine when a/c on.

So, to solve this problem I started replacing things that might have an effect more directly on the idle regulation, rather than a/c components. The AMM is less than two years old, so I cleaned out the throttle body (I found it was sparkling clean anyway), replaced its gasket, checked the spacing on the TPS (it was fine), listened to the injectors (no apparent problems), checked for vacuum (fine), and gave the car a nice pat on the head. All of this changed nothing. I have a new intake manifold gasket ready to go, but I'm getting lazy.

On a possibly related note, fuel economy is probably not what it should be, staying in the 18-21 mpg range for city/highway mixed tanks, though now I'm just nitpicking.

Any wise ideas?