Just curious what most of you guys use as far as oil & filters are concerned, and what your OCI's are.

FWIW, in my wife's '04 ML350, I'm using German Castrol Syntec 0w30, with a Wix oil filter. I'm also using a Wix air filter. I change the oil/filter every 7500 miles (8 months) or so.

What about you guys? Is it a waste to change 8.5 qt's of full-synthetic MB 229.5 rated oil every 7500 miles? Would I be OK using something like Rotella 15w40 for 7500 mile OCI's, or should I stick to MB 229.5 rated oils only?

Your thoughts/opinions are welcomed.