Speaker Distortion after Amplifier Install

[Nitro15]

Battery 1; it sounds like there are at least 2 banks. If so, and there is a dual bank switch, I prefer to connect the audio to the common output of the switch.

in-line fuse; if this is located in the engine bay, or shares the air space with the engine bay, I suggest this to be ignition protected.

Amp GND to bar behind dash; Direct to a battery ground post or a close main ground BUSS.

Stereo main and gnd; Need to share the same voltage as the amp. In most cases, taking these direct to the amp's power terminals is a shorter distance.

Here's a picture of my amp. It doesn't have terminals per say but rather a factory installed power/ ground harness from which you see the red & black wires. Would you suggest tapping into these for the stereo power & ground?