18x9 Black XD Rockstar Wheels w/ Toyo Open Country MT 33x12.5x18 Tires

I am thinking about putting this wheel tire combo on my new 2013 ext cab Z71.

the question is, what lift is optimal for that. I was thinking about just getting a 2.5" leveling kit but on the page that tire is on, it says that it needs a 4" lift.

but on the 2.5" leveling kit page, it says it can hold a 33 / 12.5 / 18 tire.

im confused? can someone help me out here?

 

I think the 2.5 leveling kit will be OK. I have it on my 04 Z71 and I run LT285/75R16 tires (basically a 33x11.5) and I have plenty of clearance with the wheels turned.