Anyone have any tips or step-by-steps on installing 4 new speakers and an aftermarket 4-channel amp in an '03 Taurus SE (ie, type of wiring harness, is there a factory amp that needs to be bypassed? How? . . . ). I'm keeping the factory stereo. Pretty generic question but I haven't done this in a while and I need a little push. Let me know if more details are needed. Thanks all.