Aftermarket wheel and tire questions

Like many others on this forum, I've been thinking of tinkering some more with my Prius Touring's wheel and suspension setup. So far, almost all the available chassis braces have found their way onto my car, and the handling has been transformed. Now I'm interested in giving he car a more focused look, while enhancing cornering agility some more.

Different wheels seem to be the next step. Even the Touring's "larger" (16" w/offset of 45mm and tire width of 185mm?) wheel and tire combo seems small and narrow. So what I have in mind are some 5-lug 17" wheels with 205mm width tires. My favorite wheel is the OZ Ultraleggera:

O.Z. Ultraleggera Black Painted

First, should these wheels work? The offset is 48mm. Recommended tire size is 215-45-17, but I'd probably go with 205-45-17. Second, how much of an acceleration and fuel consumption hit should I expect? For those with 17's on their Prius, is the difference noticable? BTW, weight of the Ultraleggera is 17 lbs; I'm not sure what the Prius Touring wheel weighs, but knowing may help answer my question. ...Thanks!