Hey Matt, @ToyotaMatt , do you have an image of the radio kit installed? I'm under the assumption that the speaker mounted in the glove box, and faced the corner of the cowl? I put a modern speaker in there today, and would consider running the OEM one there if it worked with my CD player. I wonder if it has to match ohms, and watts?
I checked a couple of the service manuals I have for the FJ40 AM radios, they specify 4 ohms for the speaker.