<p>It varies by school, but IMO Subject tests are important as one of the academic factors that are evaluated by selective colleges.</p>
<p>Since you already have a great Physics score, I’d recommend retaking the Math 2. I’m assuming by your coursework that you’re interested in going into something math/science oriented? Do check the school websites for Subject test requirements, while many don’t require them with the ACT, some do. And particularly if you are applying for engineering, they often have specific Subject testing requirements.</p>