Do you care if the dog is competitive at all in obedience? Or do you just want a CDX? Big difference, IMO. I think many goldens can get to a 170 3 times in Open with decent training, so you could just look for a straight show lines golden. A dog can be "meh" about obedience and pass. If you want more than that (and there are no guarantees in life, as you can have variation within the litter itself), you may want to look at lines with higher level performance titles and competitive titles. If possible, watch the relatives work. Talk to the trainers/owners. Of course the training you do with the dog is a big factor, as well.My ideal dog is a dog that I could finish in AKC, get the CDX obedience title with, probably some rally thrown in there, and then enjoy the myriad of other non performance sports that AKC offers.