If your worried about fuel economy, why spend 2k on wheels and tires?
If you can afford the wheels and tires, you can probably afford 1-2 miles per gallon. But rest assured, you will lose it. If you want some good lookin duals though i would get something like eagle alloy wheels. They make some pretty sharp 17-19s. You could go with a 17 or 18 and an economical tire and maybe not lose anything, or at least not as bad.