I play with high-res graphics enabled and can't use the insectitronics because they appear to be using the low-res graphics and it's really jarring to see....
I'm not sure if this is a bug or not, but I wish there was an option for the trons to have the high-res graphics.
I am pretty sure they should have same level of detail as vanilla spidertron does. However even if it's not the case, I don't think I can fix that, because I lack skill in 3D modeling to render a high-res spritesheets myself. (Not to mention the fact that I don't have source model for vanilla spidertron anyway)
I am seriously not sure what you mean because I play on HR setting myself and don't see a difference in quality. Maybe a screenshot or elaboration on the problem would help.