I know this topic has been beaten to death and I have searched the archives, but I have a few questions that I have not been able to find an answer to. I have recently purchased a 1997 E320 with 32,000 miles.

Did MB have a better head gasket design by 1997 on the M104 and, if so or not, what would be an average mileage for replacement (not min or max, but average) on this year? Does time (age) affect the gasket or is it mostly mileage (usage)?

Is it confirmed that there is a better replacement now?

When people say where this gasket leaks, they say at the right rear of the engine and at the front by the timing chain cover? Which side is the right rear (driver or passenger side for US vehicle)?

When these gaskets go, do they just usually leak oil externally or is it common for antifreeze to get into the oil also? What I am trying to find out here is if the infamous M104 head gasket leak also has potential for ruining the engine bearings?

What is the best procedure for checking for leaks? Should I have a service shop do it or can I see these areas fairly easily?

I have read that there are several updates to the 1997 722.6 transmission because of some design problems. Does this create a shorter life expectancy for my 722.6 if these have not been done? I don't know how I would go about doing these updates since the trans shifts just fine and the car is out of warranty (4 year or 50,000 miles), but I really don't want to have to pay for a 722.6.

Thanks for your time. I hope you all aren't too bored by my rehashing these topics.