I just purchased a 2006 Impala SS with about 20,000 miles on it. The car performs well except for the tires when on wet roads. The car has the original 235 50R 18 tires and they have excellent tread left but they cannot grip a wet road at all, in fact they are very scarey when you touch the gas pedal on a wet road. Does anyone know of a tire this size that performs well on this car while on wet roads?