Question for head porters

I have this die grinder from Makita:

http://www.amazon.com/dp/B00004YOKS/?tag=joeychgo-20

It takes some getting used to. It spins at 25k rpm. You'll want ear protection as well as really good eye protection. This thing is noisy. Also, get a junk head to practice on before you turn yourself loose on the heads you intend to use on your car.

Personally, I think air die grinders are better as you can control the speed and they are smaller which makes them easier to manuever.