i am not sure about on Karts but on road cars most brake pad material (even on high performance pads) no longer gases like it used to so slotted and drilled rotors do next to nothing as far as gas evac goes. Also the slots/holes can scrape more material off the pads so they may wear faster than on a smooth rotor
"My laptop has a webcam; if I wanted to make money while making a mess, I'd be all over the internet. Hell, you'd probably have videos of me bookmarked."
“Auto racing, bull fighting, and mountain climbing are the only real sports ... all others are games.”
It's all about having the right priorities. You can sleep in your car but you can't race your house -|- Basically i go accurately and on special lines