My factory subs are dry rotted around the foam,so a foam kit was just as mush as the speakers so I went ahead with the speakers,far as the yellow pyle speakers they look like a single voice,guy at a local stereo shop said you could wire to pos/neg leads together and run a single voice coil 4 ohm speaker i said no thanks.Again the pyle subs really suprised me for the price and not have to change anything for them to wrk get replacement in my book.