I have a set of the Hayes HFX-9 hydraulic disc brakes, and I recently had to replace the front pads. The brakes come stock with the semi-metalic pad compound, but I replaced the front pads with the sintered metal compound pads. I know this isn't a problem, but does anyone have any recommendations as to what performs better? I can already notice that the front brake is less mushy than the rear brake, and the front also has more of an on/off feel compared to the rear's gradual feel (and no, the brakes don't need to be bled). Any suggestions?