clipping distortion

Hello, I have just installed a cheapish 80 Watt Boss BVCP9685A and a pair of Alpine SPR-50C (100W) in a Mercedes Sprinter using the factory wires. The crossovers are set to -4db. The problem is the speakers are clipping (or distorting?) as soon as I get to around 30% volume with the twitters...

I wasn't sure wether to post this under "subwoofers" or "amplifiers", so i just went with The one i thought best. So, my question is exactly what the title implies. I have a kicker comp rt (10" dvc sub, 2 ohm voice coils rated at 600 watts rms and 1200 peak) i have my sub wired to 4 ohms and my...