There are a couple of additional things you need to consider, the backspacing and the roll center. Backspacing is the amount of wheel behind the hub flange. On most vehicles there's a limit before you end up hitting things like the strut tower or fender well when the wheel is turned. Roll center is just like it sounds, it's the location of the center of the wheel/tire around the hub. This measurement is important for front end geometry to work correct. Things like scrub radius count on the roll center to be at a certain place for everything to work as designed. Keeping the roll center within 1" either way is usually ok and is not as important for the rear so running a staggered setup can be done if you need larger rubber on the rear.
I don't know what the limits to backspacing are on the WK2 but I can say that visually the wheels could stand to move out by about an inch. To accomplish this you run a wider wheel with less offset.
It would be great to get the specs of the SRT8's new wheels, that would tell us a lot about how the engineers designed the suspension. Lacking that I thing the following wheels would work well:
9" x 20", 43mm offset
9.5" x 20", 40mm offset
Here's a great visual calculator: http://www.rimsntires.com/specs.jsp