Thanks for the advice folks, I'll go BIG, prolly go with a LL this time with the Coal-trol, a few hundred more up front will most likely be paid for by ease of heating. I've a retired sheet metal guy up the road a piece, he does work for me now and again, I'm sure we can design a nice ducting system to move the warm air where I need it.
I'm going to ride out this season and go shopping in the springtime for a new unit.
Forgot to ask, the top of the garage is 16ft, how tall should my Pipe be? Better yet, what height will give me the best draft?