inputs.text: pioneer 4channel amp - amp small enough install drivers seat 2003 mazda b2300 pickup truck purchased knu concepts 4 gauge install kit amazon well install previously installed pioneer head unit 50wattx4 mofset power set pioneers doors jbl 6x9s rear crew cab sounded pretty good lacked real punch addition amp powering four doubled useable volume clarity like whole new system installed much bass debated installing sub may not even need clean sound hear parts music couldnt although replaced factory sound system amp professionally installed little 100 well worth would taken much time much better install clear sound punchy bass even windows travelling highway speed satisfied