Ha sorry man, i come from an mechanical engineering background so i guess it's just how i talk.
Anyway hubcentric spacers put most of the weight on the center hub of the axle and not the lugs. Maximum motorsports makes the
best, but prepare to spend a little.
http://www.maximummotorsports.com/store/index.php?main_page=index&cPath=48_134
upgraded studs are just lugs that are hardened to they will be less prone to snapping. I don't have a link offhand but summit racing carries them as well as the major axle brands. They are cheap, maybe $20-25 for 10 for the rear and an hour or so to install but it's cheap insurance against losing a wheel even if the hubcentric spacers don't necessarily require them. Like i said before, i would run them for safety.