How much would wheels/tires like this....

I would take the numbers between the Prius liftback I through IV compared with the Prius liftback V touring. The numbers are in the 2% to 3% range for 17in vs 15in LRR tires.

I can't tell if those are 17's or 18's, but I would expect a similar 2% to 4% drop in FE off the bat even with LRR tires.

 

LRR = Low Rolling Resistance.

If you go tire shopping for any hybrid, with any wheels, make sure to get LRR tires or you will experience a 2%-3% hit. So with "normal" 17's you are looking at a 4% minimum hit maybe as much as 8%.

 

Keep in mind similar modifications to other vehicles will also take the hit. But 3% of 20mpg is 19.4% whereas 3% of 50mpg is 48.5mpg. So losing 0.6mpg versus 1.5mpg is more noticeable even though it is the same sort of hit.

The Prius' shape grows on you. I thought mine was fugly when I bought it. But I love the shape now. Its simplicity and curves are quite nice when you actually take the time to look instead of looking through the eyes of it being ugly.

Look at some of the JDM-style Prii and you can make them look very aggressive and very styled. All of a matter of what you want to do.

 

To me, 16s look just right on the C while 17s are a little big and more bling.

myself, i'm planning to go with 15s and 16s

 

Going with a larger diameter tire puts the weight of the mass further out. Think about swinging a 5lb sledge hammer around holding it half way down the grip (not to hard). Then try it holding the end of the grip furthest away from the iron. It get much harder! The added weight of going up just 1" in diameter is big. Example. One on the some of the lightest wheels you can buy for the C is the Enkei Racing RPF1 Look up a 2012 Prius C on tirerack.com
Notice that in 15" the weight is a low 9.5lbs
16" 13.7lbs
17" 14.6lbs
And it doesn't stop there. The weight of the tires for these bigger wheels even thou of a lower profile is also heavier. By going to 17" just in this wheel alone you have already added over 5lbs and that's not including the tire. Also I am not even sure if there is a LRR tire in those low profile designs. I would bet money that by going with those rims you would with out a doubt lose 10mpg. Below you will see a thread of someone on here that purchased some bigger diameter wheels and there experience. There is a lot of great info in that thread.
I too am looking at changing the wheels of C. I love the look of 16-17" wheels but am not willing to take the drop in fuel economy.

http://priuschat.com/threads/newbie-here-bought-rims-tires-omg-what-a-mistake.117422/

 

I might get two sets of wheels. First start out with 15s and upgrade to a set of 16s later.

 

You could always paint the alloys that come with the 3/4. That's what I did and I'm very happy. But I don't know how well black on black would look.

 

While I am always an advocate for getting the best mileage you can, I don't want to say that you should let best be the enemy of good. If a C with the wheels you need in order to buy it, gets significantly better mileage than your current car, it is probably worth it.

 

That's a good idea painting the alloys for my C4, what did you use: flat or glossy? And real spray paint or plastidip (I think I spell it wrong)?

 

They do make LRR low profile tires, even in 18in sizes. But they are not cheap, and I don't think you will make the savings up in the cost of the tire. You are also paying for a poorer performing tire. If your wheels are just for bling, then it doesn't matter. But if you want a good grippy tire for the 18in wheels, a 10mpg drop is probably going to happen. It might be sad to look at the Prius display and see 40mpg instead of 50mpg but you will look good while doing it. Nothing else can even come close to that "poor" fuel economy in the real world with those sorts of tires.

 

A good high quality "automotive" (or exterior sometimes it is called) spray paint in a semi-gloss with properly prepped and cleaned, and cleaned again, and cleaned once more will look OK. On the Prius it might last longer than most cars since the regen brakes don't heat up as much as pure friction braking. But the paint will discolour over time.

The best option nowadays is to powder coat. Within the past 3-4 years they have been able to get powder coating techniques so that the bake cycle is short and the temperature profile is closely matched for heating and cooling. This prevents weakening the aluminum that many aftermarket rims are made of. Aluminum doesn't like heat stress, it becomes brittle but then you can do a slow heat and soak to get it strong again. Weird metal.

For your wheels though, professionally powder coated is the way to go. If you want black, that is no problem. If you want colour matching to your paint colour paint would be cheaper.

 

Plasti-dip in flat. But you can do it in any color you want now, as long as you have a sprayer. I used the spray cans. Cost me $30 after tax. 4 cans.

 

It helps to know what the dimensions you want are. I think there is only 1 option for the 17" tire though. It can be found on the aforementioned thread.