can't help you with the 18's, but i am running the 19" version...
http://www.zpost.com/forums/showthread.php?t=658931
quality at 2 months in is quite good with absolutely no issues to report. the true test will be one year in. the only real downside, which is an attribute of all replica wheels, is they are on the heavy side. you will not notice this if you are not tracking the car.
also, here is a great resource for non-///m wheel fitment...
http://www.zpost.com/forums/showthread.php?t=398990
edit: found this website, they appear to have better offsets available for the same product...
http://www.oemwheelsplus.com/