Running the game from a USB drive protects your original disc from wear and tear.
It is important to note that the official developers, Chadsoft , do not distribute CTGP-R as a pre-built WBFS or ISO file. This is largely due to legal reasons and their commitment to "anti-piracy" measures—the mod traditionally requires an original Mario Kart Wii disc to run on a console. ctgp revolution v103 wbfs updated
refers to a specific update revision of the CTGP-R package. The “WBFS updated” designation indicates that this is a pre-built WBFS disc image of Mario Kart Wii that has been patched with CTGP Revolution v1.03, intended for use with USB loaders on a modified Wii or Wii U (vWii). Running the game from a USB drive protects
CTGP Revolution v1.03 WBFS: The Definitive Guide to the Ultimate Mario Kart Wii Experience refers to a specific update revision of the CTGP-R package
CTGP Revolution v1.03: The Definitive Custom Mario Kart Wii Experience
While "Custom Track" WBFS builds exist on some community sites, they are often , lack the CTGP-R online features (Ghost database, 200cc, Wiimmfi), and are generally considered "piracy" versions that the developers do not support.