I recently installed these under the bumper on my '99 Suburban (with the lens properly oriented for that usage), and they are awesome. Great beam pattern, with a very sharp cut-off. They throw light wide and just in front of the truck, which is exactly what fog lights are supposed to do. We had some snow and fog in my area recently, and these were a great addition that made it easy to see what was in right front of me and just off to the sides.
I used my own custom switch, relay, and wiring setup, so I can't comment on the wiring kit that comes with these lights. It looks like a reasonable wiring setup and has good instructions, I just wanted a more custom install on my rig with switches that were better integrated into my dashboard and to use a custom wiring harness to drive all of my improved lighting (fog lights, driving lights, relay kit on factory headlamps, and extra back-up lights) without having a mess of wiring all over the place. For just adding one set of lights, the wiring kit should be just fine.
NOTE: If you break a lens on almost any Hella light, you pretty much have to buy a replacement single lamp, which is about half as much as the cost of the original kit. If you can even get a single replacement lens by itself, it's usually just as much as buying a single lamp. I found this out the hard way because my wife had the bad luck to hit an errant box that was bouncing around on the road and it caught one of these fog lights hard enough to crack the lens and nearly pull the light off it's mount. The light still works and was able to be adjusted again, but it's only a matter of time before the lens fails completely and falls out. Maybe the rock covers that come with the lights aren't such a bad idea to leave installed, but I use these lights enough to make the covers a hassle to remove every time I want to use them... Maybe if the lights weren't so darned good I wouldn't be tempted to use them quite so much... :-)