Nice clean work in the boot mate, nice to see you have taken your time on this and got the results that show all your hard work.
A few questions and pointers about your wiring though, I hope you dont mind some advice

What batteries have you used on this? I ask as they look like marine batteries, marine batteries are not really suitable for this application as unlike automotive batteries they are designed to take long slow discharge until nearly flat and then recharge, they are not really suitable for heavy duty discharge and charge like this.
I cant see a fuse on your feed to the amps where is it?
This looks like the standard alternator, in which case the cable you have used us way over the top as the standard alternator only pumps out 70 amps max and that is when it is new and only for short periods. So that cable is about 10 times bigger than you need. You would be much better connecting the alternator output directly to the battery rather than adding an extra connection to the starter, we all know how quickly the starter connection gets covered in cr_p and spoils the connection.
You did solder all the connections to your power leads didnt you?
Running the speaker wires so close to the instrument cluster is not a very good idea as you are likely feed interference to the instruments that could affect their accuracy and even the life of them.