Thanks, Jeff. I'm looking forward to others' thoughts as well.
I've run blanks and Zimmerman slotted and/or drilled for the last 15 years. I probably have about 100 track days and could never tell a difference between them other than maybe a slight grinding noise on the non-blanks. I've tried both on a highly tuned A4, Boxster S, E30 and now BRZ (OEM only). I've never had a problem with rotors warping, regardless of what they are.
Again, thanks for the feedback, and I look forward to what others have to say about this.