A Lua script that aims to be helpful for creating tool-assisted speedruns for Mario Kart DS.
This script shows a bunch of information in text form on the bottom screen, and some information about collisions on the top screen. Use the view collision button to see a 2D top-down view of your kart's hitbox and nearby collision surfaces. Then change the viewing angle with the < and > buttons. Press < once for a 3D view from the camera.
Using a button you can toggle between viewing information for your kart and the ghost's kart. You can also use the copy from player button to copy the inputs (recorded by the game itself) for the current race, to the ghost. The Lua script will automatically rewind to sync the ghost (though this may fail; if it does, manually rewind until it does sync and modify an input in TAStudio there). It will also rewind if needed when you load a branch. Click the button again to stop auto rewinding/updating ghost inputs.
Most of the information displayed by the Lua script is explained on the MKDS Game Resources page.