I tried to match the nuts locally, and was told they were phosphor bronze and not in stock. I would definately get the studs from a Mercedes parts source. Call Phil or Rusty. You are talking about material selected for the high-temp mixed-metal environment it is required to perform in.

If you are asking if you can replace studs with Home Depot bolts, you are asking to have your head retapped when they suscumb a lot faster than your studs. You will not find out until you forgot you put them in, it is 24 below zero and you are late to work.