As far as oil filters go, there have been members here that have removed flattened filters on an oil change .
Most commonly an after market type filter .
On a cold start oil pressure easily exceeds 100 psi, our moderator here Justin B., put an oil pressure indicator on one of his airheads, can't remember exactly the readings, but it was a bit of a shock to see these pressures .
A general consensus is to use the OEM 'bendable' two part oil filter, it seems to stand up to the pressures, haven't heard of any of these collapsing .
If you do go with OEM 'bendable' or hinged filters, there are two types, one for bikes with an oil cooler and one for bikes without an oil cooler, it does make a difference .
My personal experience with full synthetic oil  ( Mobil 1 motorcycle oil) in my '81 R65, was the rear main seal started leaking within a few months of putting it in the engine .
I replaced the rear main seal and it started leaing about a month or two later, drained the Mobil 1 out, put Spectro 'Golden' oil back in and have not a had a problem since ( 12 years now) .
Other members here have not had a problem with full synthetics in their R65's .
I've been using a filter from Visufilter for about 5-6 years now, no problems yet with them .
http://www.itw-fastex-cva.com/images/stories/data-shts/visufilter/8437-00-9909.PDFSince installing them, I have not gotten the usual deposit of fine grit and a couple of globs of water in the float bowls when I removed them for yearly cleaning .
They've got about 10 sq. cm of filtering area .