In the absence of facts, the common feeling around here is that an MB engine is not worth the risk of an untested filter. Mann, Hengst, Mahle and Knecht filters are all known to keep MB engines happy. I couldn't tell you what's in any of my MBs at this moment but I know it's one of those brands.
Thanks for the response, but is there any particular reason WHY a Wix filter is unsuitable? Don't try and compare Fram with Wix (other thread). There are big differences in construction and function.