As a Niro owner, I'd say the car doesn't have a lot of appeal factor regardless of the wheels you put on it. It's an economy car, not exactly a chick magnet. I knew that before I bought it, and I was fine with that. I honestly didn't want it to have much appeal factor, and look like I was trying to pretend it is something that it isn't. If appeal factor is a real concern, this might not be the car for you.
I know it's not a realistic option for everyone, but in my case I kept my Audi as a "weekend" car, for when I care about looks and performance. Otherwise, my Niro does exactly what I bought it for just fine - getting me to and from work and the mountains, cheaply and comfortably, while attracting absolutely zero attention from anyone except other Niro drivers.