Car Audio System Help!!!?

[LorenzoRusso]

Ok, I usually know a lot about audio but I'm stuck here... Ok I want to upgrade my system with an amp to power my speakers, but I dont know whether I should power just my back speakers or all of my speakers, because everyone has told me that the back speakers I have will sound great if I got power to them.

FRONT SPEAKERS
-Kicker KS60
RMS=65W
PEAK=195W

BACK SPEAKERS
-Kicker KS693
RMS=100W
PEAK=300W

So what amp should I get, should I get a 2 channel for the back or a 4 channel for all of them, and if so what power amp should I get?

I was told that this amp is good if I'm looking to power the back

http://www.sonicelectronix.com/item_22733_Kenwood-KAC-7205.html

It puts out 170W x 2 Channels @4ohms and a Bridged channel 500W x 1 Channel @4ohms

And also I was looking into this amp if I did buy a 4 channel amp, is this good?

http://www.sonicelectronix.com/item_29816_Kicker-DX400.4-11DX400.4.html

50W x 4 Channels @4ohms