I finally got around to installing my new XLR8 exhaust today and everything went great except for the fact that when screwing in the three bolts that connect to the third cat, two of them kept slipping. I had new bolts installed a month ago so I'm assuming the thread on the studs are in pretty bad shape (car is a decade old now after all).

How difficult would it be for me to throw some new studs on? Since they're only studs I can simply buy a pair from my local parts store instead of going OEM right?

Dorman 03105 Exhaust Stud | Auto Parts Warehouse

 

that'll work, I'd remove the third cat so I could work on it on a bench to replace the studs, working on it under the car would be a pain

have something to clamp the cat and hold it in place then use 2 nuts on the damaged studs back to back and tighten them together and then remove the stud by loosening it from the inner nut

only problem with a stripped stud is hopefully there's enough threads left on it to thread two nuts back to back onto it, otherwise you'll have to use one of those stud-out type tools that you just jam onto the stud and it grabs it and can pull it out

don't overtighten the new studs when you put them in

i replaced the studs in my precats, as the first time I put an aftermarket j-pipe on the car two of the nuts were totally rusted onto the studs and the studs were so corroded when I took them off all of the exposed threads that were below the nuts came off with the nuts

 

Try the 2 nut method, but you may may need some heat to get the studs out. I have, at times, removed studs and used bolts with a specific length in their place as it has made removal on some systems easier. On one of my cars, I exchange the stock cat with a hi flow unit and with the studs, the entire rear section, Y pipe and mufflers need to be removed, but with bolts, remove bolts and drop cat.

 

Did you try to run a die across the studs to retread them? Could it be that simple?