So reading the OP it seems you are comparing the 2 kits:
https://tbssowners.com/store/index.php?act=viewProd&productId=609
http://www.crownsuspension.com/lowering/2015-gm-suv-2/4-lowering-kit/
There are quite a few additional items included in Tony’s kit that after installing Tony’s kit myself I feel are absolutely necessary to dial in the ride height you’re looking to achieve and to maintain the best ride possible.
See how Tony’s kit includes these extra items:
- My autoride links (if needed for autoride trucks)
- Rear shorter endlinks which relocate swaybar
- Rear bumpstops for free travel mod
These are the items you get for that extra $200. You should do some more searching on this forum for why those 3 items are needed When lowering our vehicles. There are an endless amount of threads on those items. Until you figure that out, you’re probably not ready to lower your truck IMO.
I can tell you that the pics of the Tahoe and Escalade on the crown link have more than just rear 4” drop springs and shock extenders installed in the rear. The rear of those 2 trucks aren’t dropped a full 4” either, they’re more like 2-1/2”-3-1/2” which doesn’t get accomplished without a few more components that I do not see included in the Crown kit. Which based on your statement of only wanting to drop the rear by 3” and not be a low rider, you’re probably going to need. If you’re only looking to drop the rear 3” why are you even looking at a 2”/4” kit that has zero rear adjustability.
Also, you should clarify if your Tahoe is an LS, LT, or LTZ, does it have MRC and/or Auto-ride? All of those things can impact what kit you should really be looking to install.