have fun running it in the doors, i have an V12 alpine amp and infinity kappa's all around, i dont notice a difference. the only real thing that will affect the quality of your sound is engine/alternator noise. just make sure you dont run any of the speaker wires near any large power wires. In my opinion its not worth the extra hassle to run it directly to the speakers. Call around to decent shops in the area, and i bet they say the use the factory harness.ECHprelude said:depending how much power and how clean you want it, i wouldnt run it to the harness. run it directly to the speakers. if your using factory speakers nevermind this. but if you have nice speakers ad nice amp, why use the cheap factory wiring?