Probably no responses because no one has tried it. Even if 14" wheels would fit, and I'm not sure they would, you would have to try them to be sure to offset was correct. But why would you want them? 15" wheels with the correct offset and bolt pattern are not that expensive.
Come on; help this guy out! That would be current steel wheels from the wrecking yard made for the current batch of Toyota Corollas. The Gen III uses the Corolla wheels bolt pattern.. The Prius"v" wagon uses the same pattern as Camry wheels.
The reason I might try 14 inch wheels is that the taller tires might improve ride quality and reduce road noise
Also, I think they would look cool with "Bonneville style" smooth wheel covers. If this doesn't work right. Sorry. I'm posting from my phone, not as easy as from a computer.
The only way to really find out is to go to a wrecking yard and to get a 5 bolt 14 inch Corolla wheel and try it. A lot of wrecking yards have a good return policy.
Thinking it might be $ effective to try the michelin energy saver "as" in a 15" version first. If it's loud, adding more rubber and weight might not make it any quieter, true, more rubber between the vehicle and the road, possibly more comfort, but as the prii are after superior mileage, they seem to ride a bit rougher (less things jiggling, better mileage) and be a bit louder (less weight) might you be in the wrong car?
I just learned that all of this is moot. According to a guy I talked to at Tire Rack, 14 inch wheels won't fit over the brakes anyway, so I'll be using 15's. Thanks for the replies.