Never Cut The Stock Harness.

The best advise I can give and the worst mistake you can make while trying to install a new head unit into a car is DO NOT CUT THE STOCK HARNESS.

New head units come with bare harness with just wire ends, so you may think you need to cut off the harness on the car to wire it in.

This is the worst thing you can do. As a matter of fact, it is a bad Idea to cut any harness for anything in your car as they make wiring harness adapters to fit every thing in your car.

Before you install your head unit, go to Best Buy, or any car audio place, or on the internet and get a harness to suit the install. For instance if you have a pioneer head unit, and a 2007 Honda, you want a pioneer to 07 Honda wiring harness. This will allow your head unit to connect right into the stock wiring harness.

The same can be done for the speakers as well.