Mr heater giving off smell stinging my eyes

ANY unvented heater can bother your eyes, in the "right" environment. All it needs is not enough ventilation, improper adjustment, or chemicals in your heated space causing a reaction in the flame. This can be as SIMPLE as such things as laundry soaps, and most certainly be caused by paint supplies,/ other automotive chemicals.

The other thing to keep in mind, regardless of what these guys think, is that ANY unvented combustion heater, regardless of fuel, generates a TREMENDOUS amount of water. This means when the garage cools off, this all condenses on everything -- your tools, lathe, car, engine block, etc.