Those springs don't lower the car enough to affect ride quality a whole lot in willing to bet. Heck, when people started lowering Fusions people noticed an actual better ride with the lowering springs vs. stock.
As for lowering with just springs, stock struts will wear very fast, you'll also get rattles in your interior from the firm ride. Lowering can also cause increased tire wear from camber and toe settings being off. That's why getting an alignment is crucial. Idk if camber is adjustable in the front on the Focus but it isn't on my fusion so I'm stuck with 1 degree in front.
Regardless, none of this will really affect people lowered on Steeda springs as they aren't real low to begin with.