You can unlock King Boo by playing the Time Trial for the Ghost Raceway.
Rob is not in Mario Kart Wii.
Complete the first stages
You have to unlock one expert staff ghost in time trials
Simple, you don't, you unlock baby daisy.
You have to unlock 8 expert staff ghost data to unlock him
Sorry, I dont think giga bowser is a character in Mario Kart Wii.
You can't unlock him. You can only play as "King Boo" on "Mario Kart Wii".
Win the 50cc Star Cup.
Complete the Mushroom and Flower Cup.
Play 16 time trial races.
by getting good times on each track.
go online and look for Mario cart character/game cheats