Try some MB Quart PKC 4" coaxials, retail on em is $350 but I just order some online from
www.buyloud.com for $200 w/ shipping. They come with their own crossovers, 5 diff settings on crossover for tweeter, 30 watts RMS 80 Peak on the 4". My old car had MB Quarts and 2 of my friends have the discus line which retails about $120. All of us have been very happy with the quality/volume, I have never heard the reference premiums (PKC) but the discus speakers dont distort very much at all even when it is loud as hell. But anyways the crossovers will help direct what frequencys are being played through the speakers in the front. If you dont get the speakers with crossovers, you can get a better indash that allows you to control the frequencys go to which speakers. Or you can spend $10-$15 on a set of bass blockers so that your tiny little speakers arent trying to make bass like a 6&1/2 or subs. If you dont have anything controlling treble, mids, & bass specifically for each speaker then bass blockers are a must. If you have subs or even 6&1/2 the bass should come from the back. *When* I replenish my wallet enough to worry about spending a grand on my stereo (a while) I am going to get this JVC head unit with (2) pre-amp outs and (1) mono sub out. This means I can have the highs from the 4"s in the front on one preamp out, mids from the 6&1/2s in rear on the other preamp out, and subs controlled by the mono sub controller. You could even have the indash controlling 2 10"s and a base knob for a 12" sub. This way the front speakers arent blatting out shitty lows but crisp highs, the subs arent trying to play highs and sounding distorted. The trick to having a system that sounds good for types of music besides rap is controlling exactly what your speakers are playing and how loud for each speaker. I will be able to control every set of speakers seperatly, thus allowing the each speaker to do specifically what it was designed to do and nothing more.
Go with some high quality speakers and run a couple watts less than whatever the RMS is. I figure if I spend big now and do it right buy the almost top-end products, it saves me lots and lots of time, money and effort.