The 1:1 raw dump is exactly (4.37 GB). Compressed formats (WBFS, RVZ) will be smaller (approx. 500-700 MB).
If you are looking to explore the version, this comprehensive guide covers what makes it unique, how to play it on modern hardware, and how to get started safely. Why Choose the Japanese (JPN) Version? Mario Kart WII ISO -JPN-
Even experienced emulation users face issues. Here is a quick troubleshooting table: The 1:1 raw dump is exactly (4