While im sure that Vista has the same features as W7 - but is it possible for the power saving feature to reduce the performance of 'high' power components? Im not quite sure if i should set the power level to 'balanced' of performance load. Just a question.

I don't think you'll get any performance degredation from doing that, it will just mean that your PC will enter sleep mode if idle for a long time and some components (like USB devices, network cards, etc...) will be disabled when suspended.