I have asked this question before and still have not gotten resolved, but here it goes again. I have an 88 300se(w126) and I replaced the Becker radio with a Nakamichi receiver and sony xm radio. I now have a whine coming through the speakers and also a slight buzz. I had gotten some information previously on this board about having to change the ground wire from the factory and ground it somewhere else. I did so today and the whine did not leave. It is still there. So, I wired the deck back the way it was originally. The xm radio antenna runs along side the passenger side, so I unplugged the antenna to see if it would cut the whine out. It did not. Can anyone tell me what might be the problem? I am about to lose my mind over this problem. As you are driving the car, the faster you go, the higher pitched the whine. I hope someone else has had this problem and can tell me a complete solution. Thanks in advance.

Scott