The mostly overwhelmingly positive reviews of the 105 were critical of leanness in the midrange, a trait shared by most "affordable" digital players. I found this to be true while auditioning a friend’s 105. This is likely attributed to a suboptimal power stage IME as the digital section is TOTL. Even Dan Wright commented on how good the digital section of the 105 is sans modification, so the improvements of the MW 105 version are primarily in the power supply/power filtering (external with a large toroidal transformer) and, of course, adding the tube sections to the player’s output stage and to the power supply.
No experience with the 103.
Best to you Randy,
Dave