Everyone have a GT so it's hard for me to tell by searching. Also, it might be a difference between US and Euro..
Insurrance wanted to know the stock summer tire size on my car.. And I actually think it should be 14" rims.. The GT is 15", I'm almost sure, but the ST might be 14".
I would have to check inside my driver side door.....and while writing that I forgot that my car is a scrapped piece of metal somewhere
Oh well..