I drove the ZL1 last night with the Porterfield pads. The front ones did need some modification to fit, but no big deal. I have vertually No brake dust. Those using Hawk ceramics, These are good pads as well, had them on my Z06 and Grand Sport. I would be careful tracking them. Since these pads swap so easily, I would reinstall the OE pads which are Ferrado pads for track use.
2013 ZL1 Red all factory options
2004 Z06 Commemorative edition
2009 Siverado 2500HD
2010 Cadillac CTS (wifes driver)
2013 Cadillac CTS Coup e(driver)