Hi paulr!
I've changed my (3) non-stock locks for the SLS set (it was before the price went up!) and believe me, this makes a HUGE difference in terms of general comfort!
I know the price can look somewhat dissuasive, but I think it's worth the expense.Actually, I feel now this is one of the best things I did for my beauty, don't even imagine going back to the old 3 key system .
My 2 cents, euh...euros,sorry , conscious this won't add to your own peace of mind!
Philippe from Paris
'71 280SL manual 4sp