The M14 studs have a higher clamping load at 150 ft lbs torque rating vs. 100 for the 1/2” stud. If I was needing hubs right now, I would make the conversion to the S550 hub and order them from OP Mustang with the GT4 studs installed. The GT4 studs are longer than the ARP studs, which would be nice for spacers wider than 25mm. Then as @captdistraction mentioned above, the rear axles can be converted with a little work.I noticed that some models (Boss 302, GT500?) use 14mm studs instead of ½" studs. Not a huge difference (0.55" vs 0.50"), but there had to be a reason why Ford made that change. Anyone know the story?