Does the advertised size of the lift kit reflect the actual size of the spacer or the amount of lift that will be achieved?

 

If you have coil overs in the front then a 6 inch lift should come with a 6 inch spacer. Unless you plan on getting new front shocks. But yeah it should be pretty much right on the measurement they say

 

Lift kits are labeled by the amount of lift they give the front of the truck. For instance, most 6 inch lifts will lift the front 6 inches and the rear 3 or 4 so the truck will sit level.
Leveling kits are sold by the amount of lift they give also. A 2.5 inch leveling kit will not actually measure 2.5 inches tall when you pull it out of the box.