"GonzoKRS" has posted everything you can unlock in Mario Kart 7. Go thank him on his Google Plus page.
Here's most of it. There's more on the link.
Mirror Mode
Finish Every Cup on 150cc – Mirror Mode
Mario Kart 7 – Characters
- All Cups allow you to race as your Mii
- Get 1st in Mushroom Cup 150cc – Daisy
- Get 1st in Flower Cup 150cc – Wario
- Get 1st in Star Cup 150cc – Rosalina
- Get 1st in Special Cup 150cc – Metal Mario
- Get 1st in Shell Cup 150cc – Shy Guy
- Get 1st in Banana Cup 150cc – Queen Bee
- Get 1st in Leaf Cup 150cc – Wiggler
- Get 1st in Lightning Cup 150cc – Lakitu
Mario Kart 7 – Vehicle Parts
(These unlock in a random order for your game)
- 50 Coins – Red Monster (Wheels)
- 100 Coins – Barrel Train (Body)
- 150 Coins – Zucchini (Body)
- 200 Coins – Koopa Clown (Body)
- 250 Coins – Swooper (Glider)
- 300 Coins – Pipe Frame (Body)
- 400 Coins – Tiny Tug (Body)
- 500 Coins – B Dasher (Body)
- 600 Coins – Cloud 9 (Body)
- 700 Coins – Bumble V (Body)
- 800 Coins – Peach Parasol (Glider)
- 900 Coins – Bruiser (Body)
- 1,000 Coins – Cact-X (Body)
- 1,200 Coins – Flower Glider (Glider)
- 1,400 Coins – Slick (Tires)
- 1,600 Coins – Slim (Tires)
- 1,800 Coins – Blue Seven (Body)
- 2,000 Coins – Sponge (Tires)
- 2,500 Coins – Paraglider (Glider)
- 3,000 Coins – Egg 1 (Body)
- 3,500 Coins – Random Part
- 4,000 Coins – Random Part
- 4,500 Coins – Random Part
- 5,000 Coins – Random Part
Mario Kart 7 – Gold Items
- Gold Wheels: Obtain Minimum of 1-Star Rank on all Cups
- Gold Glider: Connect with 100 people through StreetPass or collect 10,000 coins.
- Gold Standard Body: Get a VR higher than 10,000 points or collect 20,000 coins.
- Gold Steering Wheel: Play 100 recent matches, and use the first person gyro controls 80% of the time.
- Gold Wheels: Successfully complete all Cups in 50cc, 100cc, 150cc, and Mirror mode with a “1 Star” or better rank.
