I had somewhat settled on the 1310's throughout but called into both Adam's Drive Shafts and Tom Wood's to make sure this is on-par with what they recommended since I'll be going with one of them to build my DS. The guy at Tom Wood's said 1350's for all the joints, which I was surprised to hear since so many here said the 50's could cause problems. I even brought up the fact that some had said it could cause binding at droop and he assured me it wouldn't. He also said not to buy a flange adapter because whatever they use to balance the DS will have to go onto the vehicle. So whatever I bought in advance would be wasted. Then I called Adam's and the guy said 1310's for all the joints would be the best option and it wouldn't have an issue holding up to the power I'm putting out, even with the extra stress of the 4:1 TC. So I'm kind of puzzled now.