I'm about to buy a leveling kit for my new Silverado and I am unsure which I should purchase. The upper strut round washer looking spacer or the Rough Country bottom strut adapter. Anyone with input on this?

 

You will void your factory warranty on it if you install it is all.
Lift kits are said by GM to "put to much stress on the ball joints and other front end parts, and cause premature failure." I have seen three of them come in and that has been GMs response to each of them. two 2007's and a 2008. If it is a ball joint failure or other front end parts.
Check with your local dealer or perhaps two of them before you install this option for your own good.
Sorry to be the bearer of bad news.