" some one else pointed out that if MYlink is now standard and the higher end models have the same mylink system it would just be a matter of removing the mylink unit and plugging in rear speakers."
In the tone settings for the LS there are only left and right balance controls for the front. If the MyLink is the same as in the LT I wonder if by putting in rear speakers, the balance rear controls are activated as well as the front and back fader... that would be strange.