Rough country lift questions...

[North Idaho 5.oh]

Anyone have any first hand experience with the rough country 5” lift?
From what I have read, I have to use 17” wheels? Why would I have to do that?
I have a super lift on my daily driver that has the extended knuckles and I Actually have 15” wheels on it .... can anyone clue me in?

 

[bobbywalter]

Bigger knuckle.

 

[North Idaho 5.oh]

Ok... one other question. In the description of the lift, it mentions “minor cutting” is required... does anyone know what “cutting” that may be?