Originally Posted by feta_mgp
For a turbo car with the intercooler front mounted that actually is a small opening... the Mazdaspeed 3 I had before my Focus had a MUCH bigger front grill and it had a top mounted IC from the factory.
I'm sure at some point there will be an aftermarket grill made with a bigger opening in the front, but as it sits now... if suss is correct and the openings really aren't different, you should have no issues swapping.
Although to be on the safe side... popping out the side grill pieces and using a dremel to open up some more holes would be a good idea, since they're there for show, making them functional could add that extra horizontal space the ST looks like it has.
I would recommend looking closely at the ST grille, but it doesn't appear to have a larger opening, despite looking like it should.
If the openings are the same and it seems to mirror the standard grille for the upper opening, a large closed center section and then the open lower section where the grille shutter system would sit behind. Now if some one could demonstrate this by putting the images of the lower grille side by side (where you could see what was actually open it may prove this to be the case.