A level is just either a preload spacer which compresses the spring increasing its spring rate thus creating lift, or a spacer that sits on top of the strut in between it and the mount or preload struts which do the same as the the preload spacer but uses a strut to compress/preload the spring. These push the CV axles and other components out of factory alignment, do this at to much of an angle itll cause premature wear on the boots, causing them to tear, leak the grease the keeps the CV happy and eventually will fail. Rule of levels dont go over 2.5" of level or you may run into issues..
Now a lift utilizes drop brackets for the front diff dropping it to keep the CV axles in factory alignment avoiding the binding issues.
Most people who level use the HBS 2.5" level, Bilstein 5100 struts, ProComp Prorunners which is what I have or the Rancho Quick lift.
Most of use an actual suspension lift get the Rough Country, BDS, Zone etc..