Again, we are talking about road courses when we say tracks typically. The bluing of the tires only means that the oil in the tire is coming to the surface. It can happen to any tires and it doesn't necessarily mean the tire is bad or needs to be replaced. If you want track day info, check out the track day forum here or better yet go to motoseries.com. You'll find most of your track day questions answered there. Or send a PM and we can talk offline.