So much for Apple's brilliance. I was on the phone with them for a half hour maybe longer. The tech told me to try a couple of things that didn't work. He even had to call me back after he consulted with an expert. I tried deleting and redownloading but of course it just redownloaded the exact same m4p file, which makes sense since I would expect the non DRM version of a song to have a different ID number in their database.
Stu, I followed your advice and just burned to rewritable CD and then imported them into itunes. I had to make more than one CD and the import was not completely consistent. Once it couldn't find any of the song data so I wound up reburning it. A couple of times it asked me if I wanted to overwrite the existing entries and a couple of times it just added them leading to 'duplicate' entries one being m4p and the other being m4a files.
It should be good enough for the expensive but crappy stock sound system I have in my Honda.