You talking about the del-a-lums? They are a major upgrade over the factory rubber, & aren't prone to squeaking like poly. I ran them briefly in my stock LCAs & when the arms were bolted back in, they articulated so freely. The only reason I say briefly is because shortly after I upgraded to DSE lowers which come with a very similar bushing pre-installed.
The GW's have grease fittings for periodic maintenance which is nice. Also, they won't deflect like a rubber bushings will.
Make sure before you install them in the arm you clean any burrs or sharp edges of so they go in smoothly. And be sure to use the provided install tool or something similar to help stop the arm from getting crushed.
