Hey guys, I'll bet 90% of you know more I do about these things, and I can really use your advice. Class? Anyone?

I've seen quite a number of posts regarding the location and instructions for replacing MB crank position sensors, but none specific to the 500E. Can someone tell me whether it's one of the upper locations or the lower one down at the bellhousing? How tough is this going to be for a DIYer? And what brand should I buy - Hella? Are there instructions and/or photos of the repair available? Sorry about so many questions in a row.

The car has become undependable because it will sometimes fail to restart when warm. The engine throws no code, and MB service department folks I've talked to seem stumped as to what it could be. After viewing many posts I see many others have had the same issue and seem to have been able to resolve it with a new CPS. So I've decided this is the last ditch thing to try. Do you agree?

I'm a first time poster, and thank you for your help.