Lower and upper control arms. You want to be sure those were loosened before the install and putting it back down on the ground. SS's are not the cause of DW.

 

I would recommend checking the track bar bolt hole on the frame side, if they didn't get this bolt tight the bolt will move back and forth causing the hole to become oblong. Then no mater how tight you get the bolt it will still move causing DW. Just my experience, we welded a grade 8 washer over the bolt hole making it round again and not one issue since.