Chuck, Chuck, chuck... hello, ... it would be nice to do a track day some time soon, it's been a while.
However, It seems to me that the cost of your proposal is not cost effective. You might pay what $20-25 each used tire an $60 mount and balance (x 2 if you gonna replace your street tires on your rims. Or do you have 2 sets of rims? ) = $220. + trusting your car and life to questionable used tires?! could get pretty expensive ...
![Spank [spank] [spank]](/images/smilies/icon_smile_spank.gif)
What's so special about the ones you got on now?
What pads and brake fluid you using? That's the big question.