Resistive Ignition Cables
I have tried a variety of cables and, like many hams, found considerable variation in performance, reliability and suppression. My favorite cables were made by a company called Whitaker, but I believe they are no longer in business. I like both NGK and American Standard wires, and they are still available at many auto supply shops. One of my Subarus now has a set of Beck Arnold cables that has performed very well for almost a year.
One rule of thumb that I found is that any wires that are made of carbon do not last. They initially have good suppression qualities and are cheap, but I can't recommend them. Others use resistance wire, probably NiChrome or similar, wrapped around a core. These are more expensive, but worth the money in my opinion. Some of the ones I've tried, though, seem to have somewhat less suppression than others. In all cases I found engine performance and longevity to be good.
There is a company in California that sells (sold?) high quality ignition components and related literature. The owner, Dr. Christopher A. Jacobs, wrote an excellent book on ignition systems that I can recommend. I've seen it at many auto shows in years past, and it's entitled "The Doctor's Step-By-Step Guide to Optimizing Your Ignition". The Doctor (Jacobs Electronics) also produces wires and ignition computers. I found that these were good quality but expensive. I also had some trouble with the boots coming off, too. ACCell is another company that caters to the high performance buffs, they make a variety of wires available at speed shops. Be careful though. I believe it is now illegal to use non-suppression cables on a public roadway. Performance buffs use them for off road racing.
There are also several different suppression techniques that companies use in their ad hype. I've seen such jargon such as "magnetic suppression" and the like on more expensive cables, but the ads are always a little skimpy on explanation and substance.
Cables can be checked for resistance with a simple ohmmeter. Another useful test requires only a good observant eye and a dark night. Be sure to allow plenty if time for night vision to set in, then pop the hood with the engine running. Carefully look for signs of arcing or corona. I've seen some real light shows on occasion, an obvious sign that the wires need replacement.
Finally, many of the better wires are guaranteed for the life of the vehicle. These can be obtained at Auto Supply Shops, are usually good quality, and include some of the names that I've mentioned. They usually only last a few years before I change them, but the quality is better.
One thing I would like to try is using cables for small airplanes in my car. Whitaker used to make them, but I am not sure now who is in the business. (I recall seeing Whitaker wires on a Heath(kit) airplane on display at the Lexington, KY airport!)
Two reference books I've found to be informative are:
"Electronic Ignition Systems" by Marvin Tepper published by Hayden
"Heathkit Manual Capacitive Discharge Ignition, Model CP-1060"