inputs.text: slept little amp - purchased crossfire xp600d monoblock amplifier month ago say quite impressed punch amp packs pushes 2 sundown sa12s far better previous soundstream picasso 12001d car audio head long time experienced many brands crossfire one brands deliver power efficiency claim deliver power stock charging voltage level also like power ratings based real world voltage level 138 rather manufacturers ratings based upon 144v still sometimes wildly rated power claims means factory charging systehem never hear anything close numbers claimed stock 12v car charging systehem normally sits 135144 engine running big bass dropsvoltage drops result im pulling beside people 1000w better systehems shutting thehem instant fan crossfire competition car audio buying products soon