Bob: IM S6 posted:17" wheels on a Speedster can look okay, depending on the tires chosen.
For example:
https://www.flickr.com/photos/...29/with/15766619634/
At least that's what I hope, as my wheels are on order.
There is a BIG difference between those Empi 17" wheels and the wheels in your Flickr IM photo. The spokes on the Empi wheel are much longer and the spokes on the Flickr IM photo are normal size. To me, that's the problem with the Empi 17" wheels, the spokes are too large.