Just an observation.....

Replaced the muffler on my '85 GL with one from the FLAP who dealt in
Walker Muffler Parts.  It came with a lifetime warranty and as best I
can remember (receipts went to new owner) was about $100.  Probably
needed to be replaced 3 years later when I sold the van.

Pluses - one time price
Negatives - having to redo the same dumb job again (and again....)

I guess if you don't mind doing it again and again, best price is
'lifetime warranty' (and walker does honor guarantee if home installed)
However, if and when my '90 needs a muffler, I'm going with the Stebro,
I want to do this job once, and only once.  If I keep the waterboxer,
I'll consider the stainless headers, but to be honest, after going
through two sets of gaskets on the '85 (one by the previous owner,
second by me) and the fact that my '90's had them done a year ago and
there's already weeping, my next job will be to put either the inline 4
or subaru in it....