Head unit need to be removed to install car speakers?

Factual Questions
1

Probably a dumb question… I plan on getting a head unit and speakers in my car, but I may get them from seperate places. To just install the speakers, would I have to remove the head unit to do any sort of wiring?

Or is the head unit already hooked into the existing wiring, and therefore, I could just plug the speaker in at the speaker mount end of things with no wiring needed at the head unit?

Also, I have a factory car stereo (GM) that’s 15 years old - do I need to rewire the speaker wire for the car, or will my old stuff work? I ask because I have no idea if the electrical standards for speaker wire has changed in this time period.

2

In most cases you should be able to just put in the new speakers and hook them up to the existing wiring. The speaker wires may have some sort of plug that fits the factory speaker on the end, you can either buy an adapter or cut the plug off and crimp on terminals to attach your new speakers. The factory speaker wire is usually good enough until you get into real high cost components.

The only time you may not be able to just add on new speakers is with stereo systems that have built in amplifiers like some premium factory sound or bose systems. These usually need to have everthing replaced at once.

Check out http://www.crutchfield.com/, if you put in your cars year and model the can usually tell you what speakers fit your car and if you need anything special.

3

If you’re replacing the speakers, it’s a good idea to replace the 15 year old wiring while you’re at it. That means removing the head unit. You don’t have to replace the wires, but if they’re shoddy, your new speakers might reveal that.

Your head unit is, of course, connected to the existing wiring. If you don’t replace the wires, you won’t have to change anything at the head unit.

On preview…

My friend had an RX-7 and he had to replace the wire when he installed a new head unit (he kept the factory speakers). I think there was an amplifier hidden somewhere between the speakers and the factory head unit, and he had to run new wires from the speakers directly to the new head unit.