Tires for the Z

To occupy some of my spare time, I've been researching the tires I plan to purchase for the Z when I get back home. For most people, this is a simple process. For me, it get's complicated quickly. I know enough about cars to be dangerous. I like to replace parts with better parts (read: performance). The end result is I've been calculating tire sizes all over the place to ensure proper wheel clearance and maximum tire contact patch. The Z currently has cheap 215/60R15 tires on her...and I'm looking at a wide variety of performance summer tires. I thought I had my mind made up, but two new offerings are $30 less than the Yokohama AVS ES100s I chose. I'll continue my research...and post it here....because I have nothing else to do...except torment my wife.