John,
If there is one change you can make to solve the high cost of performance tires and the short tread life that goes with them, is to simply switch from V or Z rating to H rating. H rated tires have very similar performance characteristics of V rated tires, but are half the price and last twice as long. Look at any performance car that are on their second or third set of tires and you'll find time and time again, the owner has switched to H rated tires. I have seen H rated on Vets, Porches, Benz, Z28s you name it. I replaced my Michelin MXV4s with Cooper,"Viper" directional tires, H rated, on my 850. This is my fourth summer on them and I will replace them next year with the same, I have enjoyed them that much....