A awesome fix has out for Mario Kart DX !! (from Roman Trymado)
MKDX Shader resolution fix by Nezarn
How to install and use:
1. Extract the exe and Data folder to your MKDX folder (where MK_AGP3_FINAL.exe is)
2. Run MKDX Shader Resolution fix.exe
3. Type in the resolution you want (and also set in TPUI) and press apply.
NOTE: ONLY RESOLUTIONS HIGHER THAN 1360(WIDTH) AND 768(HEIGHT) ARE SUPPORTED.
4. Wait until its finished.