I use a Pioneer avh4300dvd. It does have low RMS, but I have never run speakers with out an amp... 14-22 RMS I cant hear a difference. Now put 50-75 watt RMS to your speakers and you will certainly be set.
And you can pick up a small 2 channel 50 -75 watt RMS per channel amp for really cheap. I have found a few amps on craigslist that work perfectly for front door speakers for under $40
I currently am running a 100w rms 2 channel to some pioneer component setup for the fronts. Stock rears(just filler). And a kenwood 1000w 300wRMS mono amp to a pioneer 10". I found everything but the head unit on craigslist very cheap.