Picking out spark plugs and spark plug wires

You generally cannot go wrong with installing the same brand and model number spark plug and wire set the certified car dealership will install. In some instances, a car manufacturer will issue out Technical Bulletins or internal updates when they pick a different model.
Be very cautious when shopping online and seeing claims of massive power increases with a certain wire-set or spark plug. These claims are usually false. If you plan on using a different brand spark plug or wire set, I recommend looking at long term reviews on car forums from people who have the same car.
Some ignitions systems are very sensitive to changes and the programming is specifically fine tunes for factory equipment. You can possibly loose horse power or fuel efficiency if you pick bad equipment. Some spark plugs and wire sets are not durable. I have read complaints about the wires shorting out because the insulation around the wires was cheap. Some people went as far as slicing open the factory wire sets and comparing them with aftermarket wires. They noticed some aftermarket wires were actually thinner than the factory, this can result in less current going into the spark plug itself.
You might be tempted to buy a plug because it is advertised as being platinum or iridium. Silver is actually the most conductive metal. It was originally used in wiring of houses of wealthy owners but because it was able to corrode quickly, we use copper. To get the full benefits of a potential more powerful spark your entire electrical system in your vehicle would have to use silver as the conductor. You then would have to have custom programming / calibration on your fuel and ignition computers to be effective. Assuming you can get silver spark plugs for your car, the spark plug itself would have to be changed very frequently because it would not be made for high mileage.