Yakima doesnt officially support the Z71 with this rack, however after reading online that it could mount to the Z71, I gave it a shot.
I'm happy to report that the mega warrior works correctly with the factory Z71 rack.
I believe that Chev. recommends a weight limit of 200lbs on the roof rack, which seems to be accurate based on what loads I have tested. I think this is pushing the limits of what the Yakima basket and the factory rack are capable of though.
I have also tested the rack with the spare tire and spare tire mount which seemed fairly secure. Again, this combo pushes the 200lb limit, so there is a bit shakiness when traversing rough terrain.
With just the rack and no spare tire, I dont notice any wind noise or mpg loss. I was very impressed by the quietness.
When the spare tire is mounted, you can start to notice the extra drag on the car.
Two additonal notes for other Z71 owners, be careful about overhead clearance - with the rack you will need around 6' 10" of clearance. You will start to notice that you can't make it into certain parking garages at this height.
Also, as a failsafe, make sure to scoot the rack all the way to the front of the factory rack by moving the crossbeams forward. My fiance accidentally tried to pull into our garage, and by having the rack forward, all it did was force the crossbeams back instead of breaking the rack mounts. I was lucky, but learned a valuable lesson.
Overall, I am very satisfied.
2005 Chevrolet Suburban Z71