I had a webasto in a pickup when I was driving cross country in it. It worked good, actually too big for the small space.
I don't know anything about Planar,
Found this about the heater
http://planarheaters.com/air-heater-8dm-12
This about the distributor
http://planarheaters.com/t/aboutus
And this is the website of the company in Russia that builds them.
http://autoterm.ru/?lng=eng
These heaters do take some maintenance. I wonder if getting parts from Russia and or Canada might be a problem?