With HIDS and properly adjusted headlights, you won't blind people, these aren't any brighter than some of the new cars and trucks out today. They produce a better, wider light than when installed in projectors, I installed the same set in my wifes STS caddy and they were worse than the stock bulbs in her projectors, so after a week, I replaced them with the stock bulbs. My way is cheaper and easier than retrofitting complete housings, and if done right with 4k or 5k max bulbs will work out the best.
The problem is with the stock headlight assembly, is that it is built for halogen bulbs, and the location of the filament in the bulb.
That "wider" light is shining the the eyes of all the people you are passing on the road.
HIDs screw up the the pattern the stock reflectors are making.
The reason you can use HIDs in the projectors, is that they put a bit of metal in the fixture to block the light from going where it's not supposed to go.
Not even all projectors will work properly with HIDs in them.
Now if you have some aftermarket reflectors on your truck, they could be designed in such a way that HIDs can work in them without causing too much glare, but in stock GM reflectors, they cause tons of glare, and (at least the ones I've seen) they are brighter than stock bulbs.
One of my coworkers put the same HIDs in their stock Tahoe reflectors, and they caused all sorts of glare, no matter what way they aimed them.
If you get the projector set I found on Amazon ($97 for a Yukon, or if you have a Tahoe about $130) you don't even need to retrofit them to get good results.
I have also read that using 55w HIDs have been known to melt SOME lights.