Which brake compound gives the best stopping power, and least fade? What do each of em do, why is there grades of each kind, what's the differance, and are the more expensive ones always better? I'm looking at the autozone website at front pads for 94 Z28. Let's see we got 3 semi-metallics, 2 ceramic, 3 carbon-metallics, and 1 Z-rated. Which one would you get and why?