So, if I get a amplifier that is 2500 watts at 1 ohm, but I'm wiring it for 2 ohms which would be 1700 watts to the subwoofer, would it still require 2500 watts to power due to impedence making less go to the sub, or just the 1700 watts going to the subwoofer?
You wire to higher impedance, amp takes less power. The power delivered is about 80-85% of the power taken in a class D amplifier so thinking about 1700W delivered it will take about 2K.