I got sick of trying to hunt this down and took it to the dealer. Thanks for all the input. They determined the radio is bad. Replacement is on order.
There'* another thing though. A while ago, I had the "Service Stability Syste" message pop up, then shortly after the ABS and Traction Control went out. I let it be over the winter. It turns out there were a couple of melted wires against the headers, and the (I forgot the precise name) module that controls these is fried, probably because of the short caused. So the lesson seems to be, pay attention to the message center. Who knows if I could have saved some money having it in sooner.
2000 SSEi; Silver, Grey interior
K&N filter, removed MAF Screen, TOG Headers, 3.4 Pulley, MSD Coils, Taylor wires, 180 Thermo, Pirelli P-Zero M&* tires, J.A.T.O. Booster in trunk