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Also was thinking about using home hifi speaker cable and maybe even interconnects from QED & van den hul. Is there going to be any problems caused using hifi cable in a car?
Yes, you will get serious issues using home hifi cable in your car. Car audio amps ouput a lower voltage, higher current signal to your speakers than home audio amps. Home hifi cable isn't built to withstand this increased current without producing the dreaded skinning effect (this can be heard in the form of high frequency distortion).
Stick to a well know caraudio cable manufacturer such as Audison, Stinger, or Fusion. They make the best cables for the car audio market.
Now to turn off the sarcasim/bullshiet. Cable is cable, spend what you have to, to get the job done properly but not a penny more. For speaker and power cable the most important aspect is is it of the correct size (guage) so there is negligable resistance when the highest amount of current is being put though. For RCA's the most important thing to look at is the quality of the connectors.