You can't damage speakers with a good clean low power signal. That being said, amp those suckers. They'll sound 10x better at 125Wrms than at 14. I don't know how well (truthfully) Kicker rates their products, but I'll bet they can handle at least 100Wrms without much trouble.
The reason people say under-powering speakers damages them is not because the speakers need a certain amount of power, it's that people overdrive the internal amp in the head unit which sends a dirty clipping signal to the speakers. Clipping destroys speakers. Same goes for subwoofers.
If you amp them, you may not need a sub. My rockford components can get almost anyone by without subs. That being said, my rockfords retail at 799 USD, not really worth that IMO, but there you go.
Get the speakers set up with an amp, then decide if you want a sub or not.
2007 Cobalt Ls Manual Coupe
Kenwood Excelon X996, RF T3 Components, RF Power 6x9s, Sundown Audio SA10, RF Power T600.4, Alpine MRP-1000, Kinetic HC-1800, Black headlights, FX-R HID 55W, Custom led tail lights, Led reverse lights, Airbox mod.