First of all you need to decide how far out you intend to go with your wheels.......1/8", 3/16", 1/4"....ect., etc. Also, with stock mounting studs you will be limited...as you will want to maintain sufficient thread interface between the studs and wheel lug nuts. A good starting point is to park your Z on level ground with the front wheels straight ahead, then get out your tape measure and start checking the distance between the inner fender lip and the outside of your tires/wheels. Other things to consider.....suspension movement in bump as well as clearance when turning the front wheels. If you want to move the wheels out beyond where you can still use the stock mounting studs, you will probably need to go to an wheel adaptor, that are somewhere in the neighbgorhood of a minimum of 1" thick or wider and have mounting studs installed between the holes for the stock wheel studs. Hope this info helps you move forward a bit? Good luck!
Tom