Carbon core OE wires are a standard service item. Thay are made to be replaced at certain intervals. Just because you where still able to fire a plug with a 25k ohm plug wire doesnt mean that thay where still good. Most are junk to be honest and only do 1 thing well and thats supress radio interference so you can listen to AM radio.

I recently read "Optimizing your Ignition" by DR. Chritopher A. Jacobs who has a PH.D in electronic engineering and is the founder of Jacobs Electronics. That is a very informative no nonsense book on electronic ignitions. When I went to buy wires I took my Ohm meter with me. As far as cheap over the counter wires go I tested about 20 different brands including some of the build them yourself kits from accell. I found the bosch spiral core wires (mag core thay call them) to be about the best cheap wire available in my area. Thay test out at about 300 ohms per foot compared to my old stock wires that where 6000 ohms per foot. If you have a schucks/kragen parts store locally look for thier borg/warner nascar brand wires. These are made by bosch and test exactly the same but only cost about $25. The advantage to using spiral core wires is that you get most of the EMI supression of the carbon crap wires and much less resistance ... ohh and did I mention those $25 wires have a lifetime warranty? The spriral core wires should not wear out like carbon wires but thay still require care like any wire when handling them. Get some spark plug boot silicone grease while your at it so you dont rip the next set.

The best wires I have been able to track down are MSD but they are darn expensive. If you are thinking about buying plugs try not to spend more than a few dollars per plug. All those fancy expensive plugs are just a band-aid for a weak ignition system.