My 03 LL Bean H6 has 120k, i just bought it from the original owner lady that said it's not had one problem, i have only owned it for 3 weeks, so my own testemony will need to come later.
I've got an 02 Bean with 146k on it. Only major problem that had to be fixed was the Valve Cover Gaskets needed to be replaced a few months ago. The H6 I a great engine. Even with 146k on mine , it runs like a top!
237k miles, only significant engine work was timing chain guide replacements when very young, under warrantee. averaging about 26 mpg this time of year.
Mine has 108,000. I got it with 104,000 and promptly changed the valve cover gaskets as they were leaking severely, but it doesn't lose a drop of M1 now. Runs pretty good, getting 22 mpg, cant complain.