Compared to 32 spoke box section rim wheels, the fastest wheels on the planet will give you 0.3 mph at 20 mph (0.5 km/hr at 32 km/hr). Your hopes will be dashed if you look to the wheels (or any other equipment) for that kind of speed improvement. Only more power will do that.
The difference in my four years of average speed data (I record it religiously) was exactly 0.3mph between four wheelsets -
32/32 OpenPro with Dura Ace hubs. DT Comp spokes. 1762 grams. 257g tires.
24/28 24mm deep rims. CX-Ray spokes. 1410 grams. 220g tires.
24/28 50mm deep carbon rims. CX-Rays. 1579 grams. 220g tires.
24/28 27mm deep rims. DT Comp. 1548 grams. 220g tires.
I did some rides faster on my heaviest wheels & tires than on my lightest or most aero.