The latest update includes 4 new cups, which adds 16 new custom tracks to the already existing 50+ custom tracks this mod offers, as well as a way to configure your own cups with custom tracks you can find on the internet and aren't part of the mod by default. While more missions will be added progressively in the future, you will be able to use special tools in to create your own missions. The mod pack comes with 16 missions pre-installed.
It can be used on any 3DS running Custom Firmware. CTGP-7 is a modpack for Mario Kart 7 which adds a lot of new stuff to the game, including custom tracks and many extra features.