I have the old factory amp out of my 1999 FZJ100. When I got my rig the previous owner pulled the head unit. I put an aftermarket unit and amp in it and took the old amp out. I do not know if it works or not but have no reason to believe it does not - seems to be in good shape.
If you want to pay the shipping costs it can be all yours. PM if interested
If you want to pay the shipping costs it can be all yours. PM if interested