Hey Jon,
Porterfield has many levels of brake pads from aggressive compounds to soft compounds as you likely know. They have an equivalent to Brakeman III which works very well as an all around pad and is very similar to BIII's performance for less $$$.
I currently run Brakeman III's on the rear of my GTS and Performance Friction Carbon Metallic Pads on the fronts, but my GTS is not run on the street very often, has Stoptech slotted race rotors and brake cooling ducts (that I bought from you).
Also, I don't care about brake dust or noise with this car, I just want to be able to stop very quickly again and again from speed without any stopping or brake bias issues. I have spent quite a bit of time getting the brake bias correct for this car with track tires, 305 front / 335 rears, front splitter / rear wing, and this combo works very well, even on very hot days without boiling my brake fluid.
Brakeman III's are a very good product. I do think they are a bit pricey though.
Dan