We've run Porterfields on out 240Z with good success. They have the fronts in staock for the 280zx in a variety of compounds: http://www.porterfield-brakes.com/search.php

We run the r-4 ourselves. The Carbotech pads seem to perform a little better, but at least for the 240z the R-4's are much less expensive. We ran 1 set of Hawk blues on the car and pulled them off after 3 sessions. We still keep them with our spares, but like the Porterfields bite and feel much better.