To Answer the OP's Question, Yes it will fit, Is it needed no .
As for the Distro Blocks, If you do it for one, do it for both When people pile multiple wires on top of each other on one ground point, it causes interference
As For CCA Corrosion, Where you live is almost 0% chance , I run CCA in Ohio , and have not had any issues
OH and Dont waste your money on a capacitor its a Big Joke
Current : 2 15s 149.5@56hz 2k rms Previous Trunk box 1 18 ,146.4@43hz 3500rms,Sony 12s 145.6@63hz