I have found a company here in Seattle, (well Bellevue), that has a very
simple solution to stone chip protection on light lenses and for the
entire front painted surface on a car or truck.  I bought the vanagon
lens guards, $50.00 for all four on my '87 Syncro.  A bit pricey
considering what goes into it, just cut out plastic, (lexan?) that is
treated on one side with peel off 3M adhesive.  You clean the glass well
and apply them directly to the glass.
I suppose it will be a good solution and much more durable than the
external gaurds.  Cheaper than new lenses, that's for sure.  The web
site is www.stongard.com, someone needs to volunteer some web design
time for them though, maybe in exchange for the guards!

G'day

Mike Garske

'87 Syncro

(152k and knockin' on wood)