They are designed to disperse light from a somewhat low output source, but that doesn't mean that swapping a 55w kit is going to blind anyone.
The housings are only slightly reflective. The projector-type lens also reduces reflection. I ran a 55w 6000k vvme kit with no modification to the fog light housing and even at full output, they are not aimed in a way where oncoming drivers are getting hit right in the face with glare nor are they any brighter than the OEM HID headlights.
I've since sanded the inside of the fog light housings and painted them gloss black. This has focused the output quite a bit, but still not even close to being high enough for the arc to touch an oncoming driver even if he's in a lambo. Even at that, they are nowhere close to the scattered blinding shit that was the result of my moron neighbor putting HID lights in his (halogen reflective housing) Silverado.