There are two mechanisms of loss in the high tension plug wires (straps). One is resistance and the other is radio frequency radiation. With solid conductors, like a solid wire or the straps, you can detect the radio frequency radiation with an AM radio or other electronic device. The resistance losses are very low because of the high voltage and low current. Modern wires (modern meaning 1950-60) have a carbon core conductor which reduce the radio frequency radiation by adding some resistance. I doubt that you will be able to tell much difference between modern wires and the straps because the straps are so short, but in theory there would be a difference. To improve performance while keeping the stock look of the straps, use a modern carbon core high tension wire from the coil to the distributor cap.