J:
This matches asphalt to all to a carpet, and the condition of an especially high grip.
It is the standard foam used all over the world for some time.
X:
This matches a carpet and a low grip and matches a tire treatment well.
This foam was developed in Japan recently and showed performance by the 2012 world championship.
Z:
This matches asphalt to all to a carpet, and the condition of an especially low grip.
Evaluation of a top driver is a very good new foam. It is a different foam in X. It is very expensive.
Y:
This resembles X compound. It is easy to control. There is less wear than X compound. | 
