What are racing anti roll bars made of, and what is a typical design for them?

i'm have to design an anti roll bar for a touring car for a project at uni.... can anyone help?|||1 and 3/4 inch round steel.095 wall. No soft steel or aluminum. Must be welded completely. No gaps|||there made out of 2 inch or 2 1/2 tubular steel the design ....what ever you think will support the car best