Crutchfield is giving me these installation instructions when I add one of their radios to the shopping cart.

Are these steps really necessary?
What you need to know:

• The harness does not supply connections for the front speakers, so you will need to run new speaker wires to your front speakers.
• The harness does not supply connections for the rear speakers, so you will need to run new speaker wires to your rear speakers.
• When used in this vehicle, the functions of the yellow and red wires in the Crutchfield harness are reversed. The yellow wire supplies ignition power, and the Red wire supplies constant power.
• You will need to bypass your factory amp by running new speaker wires from the radio to the amp location and splicing the new speaker wires to the factory speaker wires at the output side of the amp.
• If you replace your factory radio, you will need to use an aftermarket amplifier with a low-pass crossover to retain the factory subwoofers.