5/8" studs are just a better deal all around. I do have one car that came with bent 5/8 studs in the Dana however it was heavier and running low 9's leaving on the bumper. The brand of studs is unknown.

You definitely want to send the axles out to drill and tap them for 5/8. Those axles are HARD! I would not want the bill for a bunch of burned up mediocre tooling at a local shop.

Also take your brakes into account especially if you have disc. It might be wise to send the rotor hats in for modification as well. That or use a step bit..maybe a reamer if you have access to a mill.