Pioneer Head Unit Question

[dan~]

Going to buy a pioneer head unit and have a question about power.

I know I need to swap the cables so Yellow - Red on both cables.

But I was reading something about the blue/white I need to cut on the pioneer loom because it can backfeed and drain the battery, which blue/white, and do I even need to that or is the loom on the pioneer already bulleted and not connected to the cars loom?

I don't have any amps or subs

Hope that makes sense