Through last year's Google Summer of Code, Lauri Kasanen began improving the Irrlicht rendering engine used since SuperTuxKart 0.7. The student developer added support for shaders and other more modern graphics features. Following GSoC 2013, another developer Vincent LeJeune began writing a new engine to allow new effects and allow support for more complex tracks.
This work is landing for the next SuperTuxKart release and will feature much better lighting, shadows, and other modern graphics features. Of course, though, this will bump up the graphics requirements if wishing to take advantage of the functionality.
This next SuperTuxKart release likely won't happen for a few months and they still have a lot of porting work to do for making all maps compatible with this new engine. Those wishing to learn more about these much needed SuperTuxKart graphics improvements can visit the SuperTuxKart blog.