Do yourself a favor and avoid the SS bolts. Don't get my wrong - I LOVE SS and use them where I can. The problem is:
A) They're generally not very strong
B) They WILL gall, especially if they get hot. The next time you pull the nuts off you'll probably get the threads with them.

I'd trust the M-B fasteners. I'll wager they put a lot of thought into the best stuff to use for that. And I'm more than willing to alter the Benz stuff when it makes sense (look at my build thread if you don't believe me!).

Dan