I believe you will be fine. Check out this previous post.
http://www.lexusfforum.com/forums/showthread.php?t=1388&highlight=spider+wheels
http://www.lexusfforum.com/forums/showthread.php?t=1388&highlight=spider+wheels
Thanks for the help. I did read that, but it was a little unclear if the OP had a staggered set up or not, as 8.5 is an option in the rear.I believe you will be fine. Check out this previous post.