matty…
take a hammer and you can crack a stud out in one or two taps…
however, putting them on with an impact wrench is not a fantastic idea… it will work, maybe, but you dont want to risk the stud spinning on its knurl in the hub… if it does you would have to get a whole new hub… i have had this happen however it was with H&R studs that were not the correct knurl
the proper way to put a stud in is to remove the hub and have the stud pressed in on an arbor press.
or you can just have one of my old rear hubs.