Instructions
Play through the Mushroom Cup and score under 01:29.670 for the Luigi Circuit, 01:37.856 for Moo Moo Meadows, 02:16.110 for Mushroom Gorge and 02:22.480 for Toad's Factory. Each course you complete under the above times will unlock a Staff Ghost. You can then compete against those Staff Ghosts on those levels.
Start the Flower Cup and score under 01:44.777 for the Mario Circuit, 02:30.764 at the Coconut Mall, 02:34.693 at DK's Snowboard Cross and 02:19.583 at Wario's Gold Mine. As with the Mushroom Cup, each course completed under the above times will net you a Staff Ghost.
Complete the Star Cup's courses in under 0:56.822 for the Daisy Circuit, 03:03.022 for the Koopa Cape, 02:58.633 for the Maple Treeway and 02:28.237 for the Grumble Volcano.
Go through the Special Cup with under 02:30.949 for the Dry Dry Runs, 02:16.802 for Moonview Highway, 03:04.836 for Bowser's Castle and 03:05.895 for Rainbow Road.
Win the Star Cup with times under 01:34.233 for GCN Peach Beach, 01:16.461 for DS Yoshi Falls, 01:06.595 for SNES Ghost Valley 2 and 02:14.799 for N64 Mario Raceway.
Finish the Banana Cup with times under 02:48.651 for Sherbet Island, 01:45.568 for Shy Guy Beach, 02:41.807 in Delphino Square and 02:32.882 in Waluigi Stadium.
Get through the Leaf Cup with times under 02:10.233 for Desert Hills, 02:58.304 for Bowser's Castle 3, 02:58.264 in DK's Jungle Parkway and 01:59.771 for the Mario Circuit.
Complete the last Cup, the Lightning Cup, with times under 01:38.880 for the Mario Circuit 3, 02:34.894 in the Peach Garden, 02:57.744 in the DK Mountains and 03:19.323 in Bowser's Castle.