Slotted and slotted/drilled rotors sacrifice surface area for heat dissipation, drilled/slotted rotors tend to be overkill due to the fact that you can't machine them and they have the cracking problem. They dissipate heat so fast that they crack eventually, I had a buddy who's Shelby did that on a track day.
I personally run slotted rotors with some Hawk HPS pads with no issues. If you just want some better stopping power keep the blank rotors, unless you want the looks of the other rotors, and pair them with a decent brake pad and some stainless less steel braided lines.
Sold - Black 2000 Mustang GT, gone but definitely not forgotten
- Silver 2007 Corvette
Current - DHG 2001 Bullitt