On my website I offer Z32, Z31, and S30/130 battery hold-downs in 1/4" polished, 3/8" chromed, and 1/2" raised Z chromed trim. I now offer them in brushed with a lacquer clearcoat. The main purpose was to bring the cost down. Each is made of 6061 aluminum clearcoated to prevent oxidation. The tie-down rods you see are Optima and Z32-specific, but I can make custom tie-down rods for your battery. The hold-downs themselves can accommodate any battery up to 6 7/8" wide.
Price:
$45 shipped for the 1/4" $65 shipped for the 3/8"
Here is an example of the chromed 3/8" ($105 shipped)installed...