I have yet to do a UOA with ARX; I'm heading in that direction soon, though.
The only characteristic I can think of that might change, although I'm not even sure in which direction, could be the insolubles. They could increase, due to the amount of crud knocked loose and hopefully being flushed, or they could be "disolved" by the ARX, and become nearly invisible.
I'll give better feedback once the UOA happens in a couple thousand miles.