new audio system through stock amplifier not "booming" please help!

[particlewave]

The 986 uses a common ground for the speakers on the OEM HU, whilst most aftermarket HUs will use a floating ground. The "adapter" is a floating ground adapter and also degrades sound a bit.
The absolute best route would be to run new dedicated negative wires for each speaker from the new HU to the output neg wires at the amp (after its gone). The car has dedicated negative speaker wires from the amp to speakers, just not from HU to amp.
This is what I did.

Thanks Bruce!

[CrisZenithBlue]

ok this is great! i am well on my way!

one question though.. i like the idea of running new negative wires from the HU. how did you run them through the firewall? did you follow the existing wires from the HU to the amp?

thanks!!