I've had KC's as well, but ,y only problem with them is there wiring harnesses. They are under rated for what they pull, I had three sets of there lights and all three harnesses caught fire and the switches actually melted. That is why I won't buy them any more, I even talked to them at Summit Racing when they were a supporting vendor. The guy just told me and my dad that was normal when running a 130 watt light, that wasn't too cool by us and we vowed never to buy from them again. If you do buy some KC's make sure you upgrade the switches at least, they only give you a 5 amp switch . We had to go to a 40 amp switch from painless wiring to handle the lights, just a little head's up.
Well my 1st choice that is actually vehicle specific for the 99-07 classic Silverado, would be the PIAA Quattro lamps. They have an 85 watt high beam bulb, a 55 watt yellow fog bulb and a built in turn signal plus a blue series vanity bulb. I actually just bought a set for my truck today for $300, other than that the OEM would be an option but they would cost just as much. If I remember right I think Pilot has lights that will fit in that spot, and they are under $100 for the set. Sorry I couldn't be of more help on that, I tend to spend a ton of money on lights LOL!
Another thing that makes those hard to find is the size being rectangular, it would be so easy if it was a round hole for the lights. Another crappy idea from Chevy, but PIAA does make the lower valance for that truck that accepts a set of 6" lights instead of the square one's. That was what I had on my old truck, except mine was meant for 4" fog lights.