^ Why do you think the action HAS to change just by swapping out saddle and pins? If the new saddle is cut to the same dimensions as the old, where's the change? Which, by the way, is exactly what I just did for my Alvarez. I installed a new bone saddle which I fashioned from a blank. The end product was identical dimensions as the original, and the action is the same as it ever was. I gained tone, sustain, clarity, and the harmonics are substantially louder and more well defined everywhere, but in particular on 5th and 7th frets, where they used to be fairly soft.
So, fsb_ben, if you want to upgrade to bone, go for it, just make sure that the new saddle and pins are a direct match to what you currently have now. Of course, if you NEED to change the action, this would be the time to do it. Mine didn't need to be changed, so I left that alone.