Yep, I think the 0w-40 is probably one of the best oils out there...
I just have to wonder how the burn rates change compared to a 15wt oil in engines with high tolerances that need the 15wt. Have you noticed increased engine use? Id imagine a lot depends on how many cold starts you do...

JMH

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (116k)
1991 350SD (206k)
1991 300D (228k)
2008 ML320 CDI (199k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (267k)

Past Diesels:
1983 300D (228K), 1985 300D (233K), 1993 300D 2.5T (338k), 1993 300SD (291k)