You might try adding a small amp to power them. With just about any HU, most speakers will start to distort at high volume. I don't know too much about your cerwin vega 5x7's, but chances are they are probably pretty efficient. A small amp with probably around 50 watts rms will make a big difference. I bought a Phoenix Gold QX 2180 to power my front and rear spekers, and it performs very well. It's putting out around 60 watts rms at 2ohms stereo. I only paid 105.00 for it from etronics.com Good luck
