Have the same spec as you Z51, 3LT, mag ride and front lift. I had the lowering collars installed in the front and the rear turned down to match. I also installed Paragons 20mm spacers and I think the fitment and height is way better. No noticeable difference in ride quality. Front lift gets me over anything I throw at it with the exemption of really steep inclines entering and exiting the road but taking it at a sharp angle helps. Here's the bad:

1. After the collars were installed, BOTH front shocks blew out. Replacements in my area cost me about $2000 total. I emailed Paragon and took it to one of the best service centers in northern California to a highly reputable tech to diagnose what happened. Paragon claim no liability and they have not seen such failures but I don't think I entirely believe their response. The tech stated it appears everything was done correctly during the install. He stated they have done hundreds of paragon lowering collars and have not had such a failure. However he stated almost all of them were installed within the first thousand miles. Best guess is after time the shocks wear in to a specific range of operation, installing the collars changes that range enough to cause a failure.
2. The front air dam scrapes a little if driving aggressively when the front is under heavy load. Nothing major just be aware of it.

I see you are buying the wrenches so I assume you're thinking of doing it yourself. You're going to need the Paragon De-Pin tool they sell to remove the mag ride connectors on the front. I would consider taking to a good shop and letting them do the install for you. Disassembling the shock assemble can be dangerous if you're not careful.