pin type versus sliders

I'm plannig on putting 15's on it when it is back together. I also plan on using a adjustable proportioning valve. I'm not sure of what size front tires I'm going to run though. It will be driven on the street though, so I'm not going to go with TOO skinny of a tire. Do you think the 11.75 rotors are overkill? If they brake too much, can't I just adjust the bias more to the back?

I just want to be able to slow it down from 125mph at the track.