everything looks good. the only comment i'll make for the benefit of everyone viewing this is in regards to strain relief.
the intent of MECA rules for securing wire is to hold it in place to prevent damage if the wire moves somewhere else and you try driving a screw there, and also to provide strain relief. the first 8" is the most important [that's what she said] and every 8" when the wire is in the engine bay or trunk is crucial.
in short, strain relief should take all stress and strain off the actual connection. the wires should be supported independently of the ring terminal connection. i don't see strain relief in this build, it looks as if all of those connections are supporting the cable. one way to test is to disconnect the nut holding the ring terminal - if it doesn't move, you're good. if it moves a lot, it's a failure point. you would know this when you make the connection. the weight of the cable should be supported independently of the terminal.
good use of techflex and heat shrink. everything else looks good. sweet amps and subs.
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