Holy crap I was JUST going over infrared heaters at work (HVAC supply company) and I was learning all about them. I was thinking "Wow, I want one for my garage".
GARAGE/RESIDENTIAL Infrared Radiant Gas Heaters by Space-Ray
Basically, infrareds heat from the ground up.. they do not heat the air. They heat objects. The ground will be roughly 10 degrees warmer then a standard direct heater. They act like the sun and are supposed to be way more effecient.
We have them to heat the warehouse I work in and will let you know in a few months how well they work.
I am considering one of these for my garage but they are expensive and you need a well insulated garage. Also, you can choose from a propane setup or natural gas.. I'm assuming most people would choose natural if you live in the cities or propane if your out in the boonies.
As for detailing, i'm assuming these would be much better then hot air blowing on your buffer and paint.