A wiring harness came with my Sony Xplod stereo but that man that runs the local electronics store told me that i need a specific $115 wiring harness for my 2002 4 dr. Pontiac Sunfire. Is he right or will the one that came with my stereo work?
The one that came with your stereo just fits the back of the stereo, not the factory radio plugs. Here's what's going on with your Sunfire: The factory radio is connected to the vehicle's data bus system, and it controls some vehicle functions. All audible warning chimes are generated by the radio, and play through the driver's door speaker. If you remove the radio, you'll lose the chimes. Additionally, the factory radio is switched on and off through the data bus system. It doesn't use a key-switched power wire like most radios. The expensive adapter communicates with the vehicle's data bus, and generates the warning chimes in place of the stock radio. It also uses the data information to generate an accessory power wire that can be used with the new head unit. You can probably find the adapter for less money if you search online. Look for a Metra GMRC-01 (also sold as the VT-GMRC-01). It's possible to install the new stereo without the adapter, if you don't mind losing the warning chimes. You'll still need a harness that fits the factory radio plugs, like a Metra 70-2003. You'll need to connect the new head unit's accessory power wire to a key-switched power source somewhere in the vehicle--you won't find a key-switched power wire in the factory radio plug.
You never need to spend that much for wire. If the unit came with wires, they will be adequate. I believe what you are witnessing is marketing psychology from companies that tout such ridiculous features as oxygen-free copper and low inter-lead capacitance, none of which produce any audible difference - PERIOD. I even saw one of these shysters advertising that their wire was burned in by running current through it for some period of time. I work in the electronics industry and while there are plenty of reasons to burn in an electronic device (i.e. solid-state circuitry w/other active/passive components), there is absolutely no value to burning in wire.
