Everyone keep in mind that when calculating where the face of two wheels will be relative to one another, you must take BOTH the offset and wheel width into account (i.e. the outer face of the 17"x8.5" +34 factory wheel will NOT be in the same place as a 17"x9" +34 aftermarket wheel).
Here is the site I have always used to compare wheel offsets: Wheel Offset Calculator | 1010Tires.com
I was comparing 17x8.5 Trophys to the 17x8.5 stockers. That's why I only had to calculate the difference in offset.