I have a 1999 4Runner Limited with the 3 in 1 single disc, I have been trying to get a 3 in 1 6 disc changer in, I haven't had any luck. I have the 15 pin plug in now. Is it possible to change the amp out with a amp with the 20 pin plug in and do anyone know if all the toyota wiring going into the amp is the same and I am open for suggestions.