I'm sorry..."unmatching tread patterns" will kill you? Oh, Brother! I bet that these same locals would do everything they could NOT to honor a warranty if you felt that there was a problem that might kill you with one of the tires that they sold you. I mean, why must you buy all 4? It's not like they're even the same size.

My Goodyear store sold me new rear F1's and I kept the Conti's on the front. Not only unmatching tread patterns but unmatching manufacturers! THE HORROR! I lived long enough that 6 months later I bought new F1's for the front.

Keep looking - somebody will sell you 2 new tires.