The stock coil leads are steel stranded core. This makes a more durable connection for the screw on plug caps.
NGK makes ignition lead splicers that allow you to cut the lead near the coil and then splice on whatever lead you chose to go to the spark plug boots. This works only if the lead insulation at the coil is properly intact. If it cracks there, then an operation to cut into the coil is required. Tedious, but doable if you have the prowess.
I can't find steel core ignition leads. (Well, unless I order 10,000 ft of it.) The best alternative seems to be copper stranded core.
I don't think the resistance wire normally commonly found in the stores is any good for use with the screw on plug caps used for the SOHC4. That screw has to bite into the core of the wire, and I would be concerned about long term connectivity.
The modern resistance wire is fine (even required) for high energy ignitions, to quell radiated energy high frequencies. The SOHC4 doesn't have that. And only needs the plug cap resistors to make the system work properly.
My 550s all use the stock 10K plug caps. Not sure you can get those anymore. I think NGK only offers a 5K option these days (or zero ohms). Pretty sure that 10K at each plug was used to extend the run life for the hotter plug used in the 550. It will run with less resistance of course, but there is no real need to do so. The resistance only has any effect when current actually flows, and has no effect on actual spark voltage, which is set by the spark gap and atmosphere in the combustion chamber.
I find there are few people that actually know how the ignition circuit is designed to work. While very simple, it uses concepts that are not simple.
Cheers,
