I ran Hawk pads on my C5 vette for years. Stopping was amazing and the dust was minimal - could always just dust off the chrome wheels easily. I considered ceramic but I also tracked the car and was strongly advised not to use ceramics while on the twisty tracks. Heat and boiling brake fluid was to much a risk.
Given the weight of the STS, I would be reluctant on using Ceramic on any type of agressive braking conditions or high speed stops. The Hawk pads are best all-around IMO. Seeding in new brake pads to rotors properly can have a huge effect on the performance and wear.