No the new blower motor will not last as long as the original.  Yes, you should replace it while the dash is out.  The darn thing is 33 years old.  How long do you think it will last??  How long will you live/have the Vanagon??  :p))While you are at it, if you have A/C, update the A/C condenser (GoWesty has a good one) and upgrade to modern coolant.  Better for you, better for the environment.  Doesn't take much.
Dave B.

-----Original Message-----
From: TJ Hemrick <x53gunner@GMAIL.COM>
To: vanagon <vanagon@GERRY.VANAGON.COM>
Sent: Mon, Apr 15, 2019 1:46 pm
Subject: Front Heater Blower opinions

  Can anyone vouch firsthand about the replacement heater blowers
performance/longevity that most of our vendors carry vs the OEM? Quieter?
Faster? More efficient? Any hard data? Seat of the pants opinions?
I'm curious as I'm about to do a full on, 100%, end to end cooling system
replacement (All stainless pipes, all silicone hoses, switches, pump,
radiator, both heater cores, etc., the works...) and while I'm under the
dash I'm wondering if I should preemptively replace the blower. I know I
can clean and lube the OEM one, but it's a toss up between "if it ain't
broke don't fix it" or "strike while the iron is hot".

It's especially perplexing because I'm that guy who you never take to Vegas
unless you need a designated driver. If I don't replace it, the OEM one
will start squealing 6 days after I finish, crap out 6 months down the
road, and I'll be pulling the dash, again. If I do replace it with an
aftermarket one, it's possibly not as good as the OEM version that (may
have) "run forever" and I'll end up pulling the dash, again. Seriously,
that's my luck.

FYI: 86 Tin Top that has not been driven for about 14 years. Yes, the fuel
system is next, then the brakes, and I've got a sweet, clean, low mileage
2.1 runner sitting on a movers dolly in my shop that came out for a Subie
swap. Sheet metal, suspension, and interior to follow as needed thereafter
with one caveat, I'll be looking at any body work (epoxy primer,
undercoating, soundproofing) on the front while the dash is out.  Cross
posted on FB VOG. Thanks.