"Is it possible to add a 2sp blower to this unit,
probably, not worth the effort or money........
and what is everyones opinion on running the blower after the furnace or a/c has shut down"
a/c ok
furnace.......you`ll get cool drafts
my suggestion look into the focus pro or vision pro t-stats
Fan option CIRC makes sure the blower runs NLT 20 minutes each hour