Are you planning to play on or an emulator ?
Most legitimate modders distribute their work as Patcher files (like .bps or .xdelta). You run a small program that merges your legal ISO with the mod files to create the Deluxe Green Edition. Conclusion mario kart wii deluxe green edition iso
Many tracks receive "Spring" or "Forest" re-textures to match the green theme. Are you planning to play on or an emulator