Just the heater. All venting, gasline, and electrical are the owner/installers responsibility. I would guess I have an extra $150.00 into mine. Gas and electric were very close just needed a little rerouting and terminal connections.
I just got a Modine Hot Dawg installed a few months ago and have been using it since it has been colder. Works great. Quiet, compact clean mount. Hangs down minimally. Pipes are extra, but super clean stainless steel is what you can get with very nice 45 degree bends in them and so on. I had mine installed professionally by a local company and don't regret it. Works well. I've got the 75,000btu version in my 26X36shop with 10 foot sidewalls and its nice and toasty in there.