The idea behind matching tires is the levels of available grip and predictability. Generally speaking, having different compounds equals uneven levels of grip front to back which drastically changes the dynamics of the car. It is up to our track chair and chief instructor to determine the viability of this option. It is always a good idea to have the same tires all of the way around your car.
BMW 325I E30 Chumpcar Race Car
BMW 540iT M-Sport (New Family Hauler)
BMW 135i Msport Daily/track toy