Curt, here's my experience...
It is possible the "D" frictions are incorrect for your application. Their effective heat range may be too low for you.
The Polymatrix D type says..."Specifically formulated for performance street and moderate to heavy dirt track use, Polymatrix "D" brake pads provide immediate and predictable response at low to medium temperatures."
If you are running slicks or race tires, you NEED a high-temp pad - MINIMUM! Slicks and race tires will introduce massive heat into your brake pads (because they are grippier to the road than street tires). The superior traction of a race tire generates severe heat in the brake pads, especially if you are coming down from "120mph". (Over 1200+ degrees)
The "D" Pads would be okay for the heat range generated by street tires and medium "open-tracking/autocrossing", but you WILL NOT be able to overpower the crazy heat generated by your Goodyear Slicks, and the pads will die in 10 minutes of competition.
This reminds me of my experience using Hawk Blue 9012, then changing to HT-10. My application had too much heat for Blue 9012. Check out the heat ranges here...
http://www.porterfield-brakes.com/hawk.html
I see you are running the Porterfield carbon/Kevlar pads in the rear. Why not try Porterfield R4 pads up front as well? I also agree with the guys on using street pads on the street, then change out to race pads when heading to the track.
And make sure fresh air is getting to the front calipers via minimum 2" duct hose.
Hope this helps!