Well, here is a neat interim pic. Not the best angle to show the true width, but these are 345's on the SST. (The drop coilovers have not been installed in this pic so it is sitting high). For reference those are 3 inch exhaust pipes with no tips... The tires are approximately 14 inches wide each.
The second pic will give you an idea of the aspect ratio off of the car. (This is the 345 on a different wheel)