In terms of performance/operations, there should be no difference between Codes 100 and 83 if both are laid with care and knowledge about rail systems.
There is an appreciable improvement in appearance due to the disparity in rail heights, but it isn't all that much. Seventeen thou in a photograph will be apparent to the discerning eye, but not to most viewers. There would be quite a substantial difference, and an evident one, if the comparison were between Codes 100 and 70. Same scene, same engine coming toward the camera, same camera position, and you'd really notice the difference. And Code 70 is much more likely to be what is found on a typical main or on spurs. Code 83 represents a hefty weight of rail that only heavy freight and coal haulers would want in place.
As for the ties and such, really, once you ballast and groom it carefully, glue it, and then weather everything to look like a real main line or well-used spur, except for joiners or spike heads, there's little to tell, not even the colours of the plastic ties. In fact, the brown in plastic ties is not very realistic, and they are too translucent and uniformly shiny. They should be dusted or painted with acrylic paints to look more like greasy, grimy and weathered wood.
Crandell