only problem with doing this is you'll have mono sound.

hey guys, for christmas i just got a new home stereo, and i noticed that on the back of the current speakers it says "impedence 4ohms" so does this mean that it runs at 4 ohms, and i could attach my 4ohm car speakers to it?

That means that it is stable down to 4 ohms (minimum 4 ohm load). You could attack your 4 ohm speakers to it, but it doesn't mean that you will have the necessary power for those speakers.