Don't look at peak numbers they don't mean anything. But do you need an amp for them? No, but they are made to be used with an amp so they will sound much better. An amp that will do 50 watts rms per channel will do ok, you're kind of limited by the back speakers wattage being so much lower than the fronts. Or you could amp only the fronts at around 100 watts rms, but I don't recommend this. If you're gonna amp em amp em all. The rear add a lot more filler and surround effect than most people think.
You also want to look at the ohm rating of the speakers. Are the wattage numbers you're looking at 4-ohm or 2-ohm?