My s280 install got loose on me. Use these to keep the install from backing out. Replaced a lost stud too.
1. Prevailing torque locking nuts. All metal, not the ones with nylon.
2. High temp thread lock. Got it on Amazon.
So far no issues!
Keeps turning wrenches on your car! You'll get better as you gain experience. đŸ˜€
Good luck!