See this thread for some help..
http://www.1addicts.com/forums/showthread.php?t=602568
I have heard that the stock setup can fit in the car... a square setup like this will be close but the tires are wider... so likely 3 in the back and one in the trunk.
265/35/18 should be fine on those wheels.. there is another thread on this someplace.. one of the tuner shops that posts here a lot has already done this.. you might could search..