Can only be tires or wheel spoke design + ET28 offset. But I noticed even at 10-20 mph speeds it less efficient than the 20” OEM Michelin. At that speed the aerodynamic impact of the wheel is negligible.
My offset was 35, but that's not counting the 4 mm on the aftermarket rotors. So it should be more like a 31 overall. Almost the only thing that would be different between mine and yours are just the wheels themselves