Hi Folks,
I am a former electronics engineer by trade, so I am not speaking 'bindly'
The point is that the OEM leads (which 'low cost' the ones I am referring to are supposed to be!)
These are based on nylon strands or filiments that are carbon coated. These go steadily higher and higher in resistance over time.
The original leads that are 10 plus years old will eventually go so high in resistance that the spark will be progressivly weaker and weaker.
Until you get erratic idiling and misfire under heavy pressures [such as acceleration with turbo pressures]
With that the High voltages from the coil packs will not be dissapated, which can then lead to sparking/tracking across the plug or the coil packs themselves. This means the coil packs themselves could fail as a result.
I experienced misfiring, checked my original leads, found them to be bad & replaced them as a 'temporary measure' with copper leads and resistor [motorcycle type] plug caps. This has been working fine for the last 2-3000 miles without any issue.
Provided the spark gets to the plugs and provides a good 'juicy' spark, it does not matter what wonderful colour they are -does it?