Mx, you aren't even CLOSE on the electrical upgrades in that quote.
Threadstarted: If you're posting this thread, you shouldn't be anywhere near a setup like that. An install of that magnitude requires knowledge, and since you asked these questions, I know that you aren't there yet (no offense intended, it's just facts). Ease into it, 4 18s with 8kw is not a daily setup for anyone but mr. S. Johnson or mr. Meade.