Wow, listen, I speak only from personal experience.  Every time a customer
comes to my shop complaining of oil light flickering at idle, all I have to
do is look up under the van and see the non-black oil filter (usually
orange), I immediately know the problem.  I have seen this too many times to
count.  The only thing I change is the filter and oil to 20w-50 and the light
goes away.  This empirical evidence plus everything I have heard about the
Mann, Mahle filter convinces me that these are the only two filters to use on
the van.  It is not so much that the Bosch or Fram, etc are such poor
filters, but the filter material actually is supposed to have larger holes in
it, thus allowing for more flow (a good thing) but actually reduces the
system pressure by a little.  The smaller holes in the Mann/Mahle filter
material screens out smaller particles and raises oil pressure to within spec
ranges.
I have seen brand new, rebuilt engines (waterboxers) in vans that folks have
taken to Jiffy Lube.  Then they call me with complaints of oil lights coming
on.  I bring the van in, I replace the oil filter, problem goes away.

I'm not flaming or anything, just sharing my personal experiences.  You can
use any filter you want, it's your van.  I could sell any filters I wanted,
but I sell Mann/Mahle filters because I have experienced a noticable
difference in quality, and it is what my customers ask for.

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
Fax:     (856)-327-2242