Those shown are from Curt Leduc at California Pre Fun. Also check out <A target="_blank" HREF=http://www.1speedway.com>Speedway Engineering</A> for stock car products. They have a great selection and are very helpful.
The picture is of our truggy. If you want a sway bar like that just call Stewarts Raceworks. We have them custom made. Usually Stock Car Product Etc. doesn't make one long enough or Strong enough. (619) 449-9728
The term "spring steel" is pretty generic. It covers a range of alloys as well as various applicable heat-treats. With the right heat-treat you can make almost any steel alloy into a spring. How long some of them will last when used as a spring is a different story. Dave G probably could give more specifics than I can.
"It only seems kinky the first time"
-- Bumpersticker seen in Lost Wages
By "spring steel" I was refering to either 6150 or 9254. Isn't this what most spring manufactures use? From my understanding 6150 is a common grade for various automotive suspension springs while race springs are made out of 9254 because its heat-treating properties, fatigue resistance and heat-treating properties are better than 6150.