I run an old Alpine in mine with the 2v pre-amp outs.
I initially tried to use the pre-amps, but even with the volume all the way up, it wasn't loud enough.
I just wired the HU's speaker wires to the amp and it works just fine, plenty of volume.

I printed out the wiring for the Alpine, and the wiring from the stock radio.
Taped the 2 sheets together and connected the dots, easy peasy Japanesey.


TASTY flashlight ?