All the parts manufactured are inspected in QC and then ratted on quality In ABCD
A are the best one with D which are acceptable level
A ones are supplied to manufacturers rest goes to dealers bug dealers usually get B or C and D ones are usually picked up by small bussiness shops
So A ones from 3s or preinstalled on your car for sure slight better than the B grade you are going to get from open market but quality difference it at max 10-15%