Fasteners are normally re-used as long as they're not corroded or stripped
in any way.  I have seen some very old VW washers crack upon re-use due to
age-tempering/ work-hardening issues.
  I only made the 'out-thinking' comment because it's so typical of so many
'rebuilders's of VW's, more often than not.
  Yes, technology has advanced over the past few decades, but not too much
in the areas you're considering.  I'm an FAA-licensed, fully-experienced
Airframe and Powerplant mechanic, and I can think of many improvements
possible in the VW designs, including the types of fasteners used.
  Nylock nuts are not appropriate to high-temp applications like an engine.
Check the specs and you'll see that.  Only High-temp (all metal) locknuts
are applicable there.
  Do you have access to  8mm, grade 8.8, all-metal locknuts?  If so, use
those, otherwise stock wavy washers and plain nuts are fine.
  Aviation hardware would be best, but is very expensive. Some hi-po
builders use 'raceware' - http://www.raceware-fasteners.com/photo.htm)
  Don't be nervous, the case edge bolts aren't under a lot of stress or
movement.  The Type 4 main case tie-bolts are critical fasteners, but if you
look at them closely, you'll notice that they are very special,
application-specific bolts and washers, the Type 1 used studs there.   The
type 4 is vastly improved and updated by VW engineers over the years, and
the Vanagon engine contains all of these improvements.

Mike B.

I'm really not looking at out-engineering or out-thinking VW but there is
newer technology in many areas since 1983 (such as the self locking nuts)
and I thought it good to ask the question whether others found it made sense
to use it here.  I'm glad to hear you've had such good results relying on
straight torque for performance, in mission critical moving machine
applications I've always had to use Nylocs or other self locking hardware so
going by straight torque makes me a little nervous, I'll just have to get
over that.

Joe