the silica enchanced rubber helps the tire wear much longer than regular tire rubber, from what I can tell. It's got this greacy feeling to it that will wear off after you've taken about 20 good hard turns.
Yes, cheeper rubber may probably be more effective if you track. In fact, it will be becuase no matter what you paid, you'll eat the piss out of them.
I'm thinking I'm gonna try the avons, and if they really do suck compairitively, I'll just drift around corners until the rears are half gone, rotate and do it again... and then just drive normally and buy the pirilli's
I must be on drugs becuase I'm not choosing the pirilli's first off... ugh... but I'm broke.