to actually beat the staff ghost data you need to beat them by 7-10 second or more to unlock the expert staff ghost
Unlockable characters and how to unlock:
King Boo - Win 50cc Star Cup
Diddy Kong - Win all 50cc Cups
Baby Daisy - Attain at least 1 Star Rank for all 50cc Wii Grand Prix Cups
Mii (Outfit A) - Win 100cc Special Cup
Mii (Outfit B) - Unlock all Expert Staff Ghosts in all 32 Courses
Dry Bones - Win 100cc Leaf Cup
Bowser Jr. - Attain at least 1 Star Rank for all 100cc Retro Grand Prix Cups
Daisy - Win 150cc Special Cup
Dry Bowser - Attain at least 1 Star Rank for all 150cc Wii Grand Prix Cups
Funky Kong - Unlock 4 Expert Staff Ghost Data in Time Trials
Baby Luigi - Unlock 8 Expert Staff Ghost Data in Time Trials
Birdo - Play Time Trials on 16 different courses/Get 250 wins online
Toadette - Play Time Trials on all 32 different courses
Unlockable Karts and how to unlock:
Cheep Charger (small kart) - Attain at least 1 Star Rank for all 50cc Retro Grand Prix Cups
Blue Falcon (small kart) - Win Mirror Lightning Cup
Rally Romper (small kart) - Unlock 1 Expert Staff Ghost Data in Time Trials
Turbo Blooper (medium kart) - Win 50cc Leaf Cup
Royal Racer (medium kart) - Win 150cc Leaf Cup
B-Dasher (medium kart) - Unlock 24 Expert Staff Ghost data
Piranha Prowler (large kart) - Win 50cc Special Cup
Dragonetti (large kart) - Win 150cc Lightning Cup
Aero Glider (large kart) - Win all 150cc Retro Grand Prix Cups
Unlockable Bikes and how to unlock:
Quacker (small bike) - Win 150cc Star Cup
Bubble Bike (small bike) - Win Mirror Leaf Cup
Magikruiser (small bike) - Play Time Trials on 8 different courses
Rapide (medium bike) - Win 100cc Lightning Cup
Nitrocycle (medium bike) - Attain at least 1 Star Rank for all 100cc Wii Grand Prix Cups
Dolphin Dasher (medium bike) - Win Mirror Star Cup
Twinkle Star (large bike) - Win 100cc Star Cup
Phantom (large bike) - Win Mirror Special Cup
Torpedo (large bike) - Unlock 12 Expert Staff Ghost Data in Time Trials
just find the character that has the kart or bike that you are comfortable with, and practice. do the solo time trials first, than work your way into the staff racing.
sometimes I think the staff ghosts data cheats.
yesterday I was racing one, and it was very far behind me, I blink and the ghost passes me and than boosts its speed like 5 times... talk about a cheating ghost