Blu Balz even looks good while on a lift without tires! ...my car would be kinda scary from that view.
Machining leaves high and low spots on gear faces which cause localized hot spots that stress the material at those points. This can lead to pitting or cracks. REM polishing is a process that uses chemicals and stones in an agitator to remove high spots left from the machining process and smooth the surfaces out as if they have been broken in. Since we do race transaxles we do this process on gear sets, ring & pinion's, diff gears, side gears, sliders, slider hubs etc. We have also done some engine components for customers.
The process takes about 8hr's. I believe the performance benefits from the process only take about 6hrs to complete however the extra 2hrs gives the parts a chrome appearance which people associate with REM. I don't personally have data on efficiency gains or extended longevity of parts however you can definitely feel the difference when rotating a transmission by hand or shifting it while it's on the bench.
.... I'm sure there is more info on wikipedia.
-Dave