The rear brake caliper mounting bolts on my black Crossfire required a 16 mm wrench or socket yesterday. No torx bits were needed for the caliper mounting bolts. I used a 4 mm Allen wrench to remove the rotor retaining bolt. However I ended up stripping one of those bolts, and for a time I thought maybe I should've used a no. 30 torx wrench. But it was hot. The Allen wrench worked fine when I put on the new rotor retaining bolt back on. Torx sizes were not involved.

The manual for the car says I should've tightened the mounting bolts to 21-30 foot pounds. However, I could not fit my torque wrench--maybe that's what you're asking about--in there to tighten the caliper bolts. I had to estimate on that one.