Good call C-H!.
Most Voltage Stabilisers that I've been associated with, have been of the Auto-Transformer type.
However, I can't say that I like the idea of the A-Transformer, there are Regulations here that limit thier use to 5% of input voltage, for safety reasons, one of them being, if there is a short-circuit in the Primary/Secondary winding, the output load recieves full Primary voltage.
Another thing that I must ask, are these Transformers made for continuous duty?, as they would be supplying a computer system.
Heat build-up in a transformer is usually thier biggest killer.