While I agree it was done to compete with the Trailblazer SS, I don't think it was trying to compete with the Silverado SS since the Silverado is a truck and not an SUV. Is the AWD system used in the GC SRT-8 the same the AWD system in the LX cars or if its the Quadra-Drive II. If it is the Quadra-Drive II, it might be the case that the 4Matic based AWD system used in the LX cars cannot handle that level of torque.