Just to bring some closure...I installed the Scosche OEA-4. It works great. No popping, no hiss, great sound, normal volume. I adjusted the gain of each channel to to about 3/4 full, and the volume is a bit higher than normal without distortion. If you're having a problem, I suggest this amplifier a...

ilquikgtx, I had originally thought of that, but the factory amp doesn't have RCA inputs. It only has regular speaker wires, so the SNI-35 is backward from what I would need, just like most line-level converters. The Scosche OEA-4 does the exact same thing as the SNI-35 but has high-level inputs and...

I have this exact same problem. I was told it might be a grounding problem. I'm going to run a ground wire from the back of the head unit to the amp to make sure they are using a common signal ground. If that doesn't work I will go back to using the high-level speaker wires (instead of the RCA plugs...