JC,
I think a pair of K140G's is a great choice, as the YAK is a very large and draggy plane and the 140's will give you the ability to fly it with authority and plenty of vertical. Again, another reason we got into turbines is the go fast and the pure thrust of turbine power. Aside from the cost difference of the 2 turbines vs 1, the only extra cost for the twin setup is a Y connector and some extra fuel line. If you decide to go with KT turbines, let Barry know when you order them to get you sequential #'d turbines and I will tune them to match on the thrust output for you.
K210G = $3,850.00
K100G = $2,050.00 x 2 = $4,100.00
K140G = $2,450.00 x 2 = $4,900.00
Dirk
KingTech Service