Sunburst's proportions and color choices were changed in the 0.16 update. This mod adds the original version of the Sunburst as a separate vehicle. It is fully compatible with 0.16 and doesn't conflict with the official version since it has its own folder, jbeam, models and textures.
It is called "Hirochi Sunburst Legacy" in the vehicle selector and its internal name is "suncurve".
Mods for this version of Sunburst are welcome, for example, old mods that require a lot of time and effort to be made compatible with the new Sunburst, unlike this one.
Hirochi Sunburst - Legacy Version 1.0
The pre-0.16 curvy Sunburst