My wheel dreams crushed or, how heavy is too heavy?

[Yaristeve]

I've been looking for a set of new rims. I always liked the look of the Ronal Turbo R10 and learned that it is now possible to buy them in the US:

http://www.ronalwheels.co.uk/?page_id=25.

My plan was to strip them and powdercoat them all white (my Yaris is white). I think aero style wheels suit the Yaris' style/shape perfectly. They come in 15 X 7 38mm offset.

So what's the problem? They weigh about 18pounds each!! They were, IIRC, originally made for rallying and like ALL rally wheels, they are heavy.

I am an engineer and I also have a Miata which really responds to LIGHT wheels. I have a set of Volk TE37 (15 X 7, 9 pounds each) on my Miata. So, I find it difficult to wrap my mind around 18 pound wheels on such a small car.

How badly do you all think wheels this heavy will affect the ride, handling, gas mileage of the Yaris? Should I go look for more traditional wheels?