Hello guys, I have my system now in the car. I just wonder, do you need a capacitor or not? If so, is there little K.? I know the ones from earlier these round “bombs”. 😉 Audio: Front: MB Quart RUA 213, Rear: Alpine SXE 1725s, Subwoofer: Rockford Fosgate 10″ P3SD410 Shallow Amplifier: Rockford Fosgate Punch P400-4 <--400Watt Thanks for your answers.