I replaced the studs on my hubs which came with the Speedtech Extreme subframe while the suspension was assembled. It's a little tricky but can be done. As I recall I used a large C-clamp with a socket on the back side to 'press' the old stud out. Then I used a bearing-style tool which allows you to pull the new stud in and seat it. I believe this one:
https://www.amazon.com/Lisle-22800-W...ce-g7448806443
It takes some effort to do but can be done. I think it may be harder to do if the hub is removed from the spindle. In my case, having the suspension assembled helped to support the hub in one direction while I fought to push out and pull in the studs in the other...
Good luck.