Thank you.
What tires come on the standard 4WD Tahoe? Do dealers allow you to swap tires?
What specific skid plates should I add to a non-Z71 vehicle?
What shocks come on the Z71 and which ones are on the standard vehicle?
Dealers will probably not allow you to swap wheels or tires unless you are buying them.
Adding a skid plate really isn't a critical thing particularly since the non-Z71 has that spoiler. You would end up ripping that thing off well before hitting anything on a skid plate. But, you can remove the spoiler.
You might not want to pay all that money and create a "Franken-Tahoe" by having to remove spoilers, add skid plate, swap tires, etc. That's stuff that people typically do over time. Driving a brand new vehicle off the lot and doing that might not be the best thing. Just my opinion.
I'd say to go out and drive a Z71 and non-Z71 back to back and see if you like it. You might hate it or find that it is for you. Might save you a lot of money and headache in the long run.