All original F-Zero X tracks were replaced with this track pack called "F-Zero X 2nd Boost". Made with the F-Zero X Track Editor.
Preview here:
F-ZERO X (U) [!].z64
CRC32: 0B561FBA
MD5: 753437D0D8ADA1D12F3F9CF0F0A5171F
SHA-1: 5F658E88FFA9DE23CBA6986A8FD3D3A90D7B4340
SHA-256: 2BE0F861C30752BBDFA727753A454108BC973C27AD814744F191B1278C1F482D