Yes, they get really hot. They will glow red, or sometimes even orange, if you have just climbed a hill under turbo boost. That's why it is important to let them idle for a minute or two before shutdown to help the turbo cool. When shut down while still red hot, the oil that is inside the turbo will tend to "coke" up, and will eventually wear out the bearing. The water-cooled units still get quite hot, I have one, but they don't get quite as hot as the oil-cooled ones.