My experience with the 4BST is that it doesn't get so hot that you can't keep your hand over it. What kind of cables are you running to the speakers? High capacitance cables succh as the "Goertz MI" series can cause the amp to run hot (in my experience).
My 4B-ST runs Hot
4B-ST owners, does your amp run hot? After an hour or so of listening at moderate levels my amp is so hot on top that I can't keep my hand on it for long. I do not think I am pushing it that hard, but I might be wrong. My speakers are some small floorstanding PMCs (FB-1). Curious if anyone thinks this is normal or might be a problem?