Here's 2 shots of my sports bug from similar angles with 15" and 17" tires.
This shot is 4 sports bug rims, 5.5 x 15 ET26 with 185/65 15 tires.
Same car, with the 7 x 17" ET55 rims with 205/40 17
Hope this helps a little bit. One thing to consider is tire cost (I chew through a lot of them). I can buy 1 set of very sticky street tires for the 17" rims but with the same money I can buy nearly 2 sets for the 15" rims.