Easily the greatest racing video game to ever grace the Earth. Anyway here's my stupid 96 course tier list-

F TIER
96. GBA Cheese Land
95. Wii Mushroom Gorge
94. Bone-Dry Dunes
93. Ninja Hideaway

D TIER
92. N64 Yoshi Valley
91. GBA Sky Garden
90. GBA Sunset Wilds
89. Tour Tokyo Blur
88. 3DS Toad Circuit
87. Tour Paris Promenade
86. Tour New York Minute

C TIER
85. 3DS Rock Rock Mountain
84. Water Park
83. GBA Snow Land
82. N64 Toad's Turnpike
81. Sweet Sweet Canyon
80. GBA Boo Lake
79. Cloudtop Cruise
78. GCN Dry Dry Desert
77. N64 Choco Mountain
76. 3DS Rosalina's Ice World
75. Wii Moo Moo Meadows
74. Wii Grumble Volcano

B TIER
73. Sky-High Sundae
72. Mario Circuit
71. Twisted Mansion
70. Dolphin Shoals
69. DS Peach Gardens
68. SNES Donut Plains 3
67. Tour Amsterdam Drift
66. GBA Mario Circuit
65. DS Wario Stadium
64. DS Shroom Ridge
63. Tour London Loop
62. SNES Mario Circuit 3
61. Wii Wario's Gold Mine
60. Rainbow Road
59. Thwomp Ruins
58. GCN Sherbet Land
57. 3DS Piranha Plant Slide
56. Tour Bangkok Rush
55. Tour Rome Avanti
54. Mario Kart Stadium
53. Shy Guy Falls
52. Wii Daisy Circuit
51. Electrodrome
50. 3DS Neo Bowser City
49. DS Mario Circuit
48. Tour Los Angeles Laps
47. SNES Rainbow Road

A TIER
46. Squeaky Clean Sprint
45. Ice Ice Outpost
44. Super Bell Subway
43. SNES Bowser Castle 3
42. N64 Kalimari Desert
41. Wii Koopa Cape
40. 3DS DK Jungle
39. Bowser's Castle
38. GBA Riverside Park
37. Tour Madrid Drive
36. GCN DK Mountain
35. Mute City
34. GCN Waluigi Stadium
33. Dragon Driftway
32. Tour Berlin Byways
31. Wild Woods
39. DS Cheep Cheep Beach
29. Merry Mountain
28. 3DS Music Park
27. Tour Sydney Sprint
26. GCN Daisy Cruiser
25. Animal Crossing
24. Tour Athens Dash

S TIER
23. Piranha Plant Cove
22. Tour Vancouver Velocity
21. Excitebike Arena
20. Wii Moonview Highway
19. Wii DK Summit
18. Hyrule Circuit
17. Tour Singapore Speedway
16. N64 Rainbow Road
15. DS Tick-Tock Clock

SS TIER
14. Wii Coconut Mall
13. N64 Royal Raceway
12. GBA Ribbon Road
11. GCN Yoshi Circuit
10. Toad Harbor
9. Sunshine Airport

SSS TIER
8. GCN Baby Park
7. Yoshi's Island
6. Wii Maple Treeway
5. Big Blue
4. Wii Rainbow Road
3. DS Waluigi Pinball
2. Mount Wario
1. 3DS Rainbow Road