My track setup is 18 inch Apex Arc 8 wheels with Hankook Ventus R-S3 that were shaved. The sizes are 265/35/18 front and 285/35/18 rear on stock suspension. Talk with Harold at HP Autowerks for a great deal and check out this thread for more info:
http://www.1addicts.com/forums/showthread.php?t=631811