The SL 600 front brakes do handle the abuse better-I was able to switch from a full race pad to E-spec "Textar Yellow Box" pads. I run primarily @ Lime Rock, which has one big braking event (120ish down to 60ish) and 2 small braking events in its 1.53 mile circuit.
Nice pics, Bri! Indeed they are a bit ponderous, but do better than you'd expect. Brakes are super strong, and there's a pretty solid amount of power. Would love to lose 500 lbs. though