Dr. Diff 13" vs 12"

Wondering what the better front brake option would be to run along with my Dr. DIFF 11.75 rear disc. Originally his 13" front kit is what I plan on running but recently I noticed he offers the 12" kit with Wilwood calipers. The car has 18" wheels but maybe down the road I'd like to have the option to run 15" big and little for that street/strip look. Your thoughts?