Pretty sure the ST gets 19's and 245 tires.
This guy's running 19's and 20's with no problems
When you get a wider wheel, you want a lower offset and a narrower tire to push the wheels out further from the hub and make sure you clear the inner fender.
I plan on running a conservative set-up: 18x8 +45 with 225/45/18's. No drop til warranty expires.
We can run 235's (Titanium factory width) but I want to keep my gas mileage close to where it's at.
Check these out: