Thanks USAFPILOT. That is a big deciding factor, and it's nice to hear from someone running the same car and wheel. I had heard that about a Z06s hooking so hard they broke stuff, but that a was on a 19" and I think in a 335. Your experience with a Z is far more valuable to me than all the C6, Mustang and SRT8 forums' info on these tires. That's why I wanted to start this thread!
On the 555R, they are actually an older tire. You can read here:
http://www.zr1.net/forum/showthread....highlight=555r , and on a few other posts that people were happy with them. It even looks like Haibeck had recommended them. I just worry that the Drag Radial might be a little too soft a sidewall for cornering. It sounds like the 05 might be more of a compromise between both worlds.