I had a set of the old original SS springs on my car ran good for years, when it got to running low 10's I bent one. Bought some new ones before I knew they were being made in Mexico and bent three sets in one season. I found out they were made in Mexico when I took a set apart and it was written right on the spring. Cal Tracs at that time were just coming around, and I could do the work myself so I just did a 4-link and never looked back. My advice is if you are in the 11's SS springs work pretty good, 10's and faster and use cal tracs or a 4-link. I like the 4-link and it works great, but if I knew cal tracs would work as good as they do, I would have went with them at the time.