Just wanted to update this thread. After burning a few seasons as an early EPA stove with no liner (slammer install) I installed a 6 inch liner. Got it from a friend who installs, it's an ovalized flex for about 8 feet and the rest is rigid. Got it for free actually.
No insulation. Runs inside my 10 inch square terracotta chimney. Install was straightforward, cutting out the metal damper structure, and breaking out a row of bricks.
After using for a few weeks it's pretty amazing the difference. Before it would overfire very easily, making the room very hot. Now the size doesnt appear too big for the house, and it'll freely burn without making the room an oven. Starts real easily, burns freely even with the damper choked down. Smoke is light coming out of the pipe, versus the smoky McChokerson that it did before. Hard to see the smoke actually. Definitely worth the trouble. Thanks everyone for the help.