Amps cant be 2 or 4 Ohms. They produce different amounts of power when the sub is 2 or 4 ohms. So if the sub is 2 ohm your amp will be shooting out 750 watts rms, and if its 4 ohm it would be lower. Cruthfield has wiring diagrams so you can get your specific diagram to see how to wire the sub.
http://www.crutchfield.com/S-oe7cQQk...rs_wiring.html
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