The rollbar was installed by George Diagne from Westside Performance in Los Angeles. Rollbars can be made from either 4130 chromoly or mild steel. Mild steel is less expensive and can be MIG-welded together, but it adds weight. Chromoly is stronger and therefore lighter because a thinner wall can be used, but it needs to be TIG-welded adding cost and complexity. We chose to use mild steel with a requirement of 1 3/4-inch od x 0.118-inch thickness.