I decided to sign up to the forum to give some input (even though I do not have a tahoe).
The bumpers on Z71 tahoe's are actually just a 6.5l Diesel bumper. You can get them paintable, with impact strips and bumperguards, or smooth without.
I bought a chrome 6.5l diesel bumper and installed a second set of 88-89 sealed beam headlight adjusters behind the bumper, with GE 100,000 candlepower spot lamps in the openings. The size of the 88-89 sealed beams are almost the exact same shape as the opening.
The factory sport airdam and factory foglights are also a good option. The factory foglights do a pretty good job of lighting. I upgraded my lenses with KC LX2 foglamps, which fit in the factory housing. The sport airdam also has the markings for factory tow hook openings (located on the backside) where you could cut them out. I am running aftermarket hooks in mine.
Diesel bumper (prior to factory fogs...)
Lights on
Lights Close up
KC Fog closeup
I have been really happy with my setup, I run the fogs with the lows, and all eight lights are on for high-beams. If you have any questions shoot me an email....