I just replaced mine with the seal from GoWesty.It is not the same as
the original seal at all but the quality seems very good.The channel portion
of the seal which wraps around the poptop seems to be made of sometype of
impregnated "canvas" which is then bound to a circle of rubber which seals
the poptop to the body.I would suggest buying the entire poptop kit which
includes the roofrack seal, the poptop seal, and the seal under the roofrack
and the adhesive, for I believe it was $79.The only thing to be concerned
with is that the adhesive is black and can be messy if used in excess
especially if your poptop is white I feel a clear sealant would be easier to
work with .Also, don't let the roofrack bolts fall down inside your bus!.I
tied a tiny piece of wire to each to prevent this from happening.
    I shopped around and the kit from GoWesty was the most
affordable,especially considering Vw. wanted $500 for the original seal !!

        woody
"keep on pushing"