We present this information with a hint of sarcasm, but spring steel is hardened, heat-treated, high-carbon steel. Heating it with a torch changes the characteristics of the spring and could possibly create an area where cracks will develop over time. In my defense, the area heated was just enough to create a pigtail end. I did this outside of the car, so the springs weren’t loaded, and I let the them air cool rather than quenching them and possibly creating an area more brittle than the adjacent metal. I’ve put several thousand miles on the car since then as well as several laps at speed on the track at Willow Springs International Speedway, and they are fine. However, I will provide an update if things go south.