I've always heard that the horsepower:weight ratio is the most important thing to focus. And the best weight to reduce is unsprung weight. That includes wheels, lug nuts, tires, brake parts, and axle parts. I've never really heard anything about the size of a wheel/tire affecting power. But from my own experience, most professional drag cars use small wheels (14 or 15 inch). So in conclusion, I would have to think that if you upsize your wheel, but in the end the weight is less overall, then you are still in the positive.