I am up to 127 miles on the miniPro.
I have 3 units now so I am trying to keep them from getting jealous...
I have not experienced any new sounds. I still have the grinding noise at low speed but don't notice it so much outside so maybe it the inside walls making it louder.
I went by my local Segway dealer, he didn't seem to think anything was unusual.
I don't have anyone around to compare with so all the noises may be normal.
My weight does not seem to be affecting the unit or my mileage too badly.