If you want to do a 100% run and dont know some unlocks here are all of them!

Funky Kong Unlock 4 expert staff ghosts

Baby Luigi Unlock 8 expert staff ghosts

Mii Costume A Beat 100cc Special Cup

Mii Costume B Unlock every expert staff ghost

Birdo Do 16 time trials

Toadette Do 32 time trials

King Boo Beat 50cc Star Cup

Diddy Kong Beat 50cc Lightning Cuo

Baby Daisy Get a star rank on all Nitro Cups (50cc)

Dry Bones Beat 100cc Leaf Cup

Bowser Jr Get a star rank on all Retro Cups (100cc)

Daisy Beat the 150cc Special Cup

Dry Bowser Get a star rank on all 150cc Cups

Rosalina Have Super Mario Galaxy data on your WII or get a star rank on all Mirror Cups

Rally Romper (Tiny Titan) Unlock an expert staff ghost

Magikcruser Unlock 8 expert staff ghosts

Torpedo (Spear) Unlock 12 expert staff ghosts

B Dasher MK 2 Unlock 24 expert staff ghosts

Piranha Prowler Beat the 50cc Special Cup

Turbo Blooper Beat the 50cc Leaf Cup

Cheep Charger Get a star rank on all Retro Cups (50cc)

Twinkle Star Beat the 100cc Star Cup

Rapide Beat the 100cc Lightning Cup

Nitrocycle Get a star rank in all Nitro Cups

Qaucker Beat the 150cc Star Cup

Dragonetti Beat the 150cc Lightning Cup

Royal Racer Beat the 150cc Leaf Cup

Aero Glider Get a star rank on all Retro Cups (150cc)

Dolphin Dasher Beat the Mirror Star Cup

Phantom Beat the Mirror Special Cup

Bubble Bike Beat the Mirror Leaf Cup

Blue Falcon Beat Mirror Lightning Cup And the Karts and Bike options will appear for 50cc and 100cc after beating all the cups in them.