I am thinking about one of these two bikes. They have the same motor but I understand the YZ has a much harder hitting powerband but less top speed than the WR. Is this true? Are these bikes XR reliable or will they need rebuilds ala 2 stroke every year? Can the WR be made to have a YZ like hit? I want a bike with brutal straight line acceleration throughout the powerband. Which will it be? and how do they compare to the KTM 520 exc in straight line acceleration?