The larger gears overall are slightly different, but most likely negligible. The larger gears have more rotational inertia, which will very slightly reduce acceleration. And the larger gears will have a slightly higher gear contact ratio. The mesh will be just slightly less efficient. Again, it's negligible. But the larger spur gear will stick down further and might get damaged more easily if you hit a rock that happens to stick into the chassis clearance hole for the spur gear.