BEAMS is a generic JDM Toyota term, is stands for Breakthrough Engine Advanced Management System (or something other gobbledegook like that)!
It is commonly applied to the 3S-GE Altezza engine for some reason, maybe because it is in big letters on the engine cover! It has nothing to do with performance or tuning.
As Rob said above it also applies to the 1G-FE engine in the AS200, you don't come across many of these in Europe, there was no real point in importing them as they are the same as the IS200.