I've beaten 3: Mushroom bridge by.115 of a second.
Sky garden by .026 of a second.
Figure of 8, 1.693 seconds.
UPDATE!
5 staff ghosts, Baby park and Koopa beach 2. Both by .172 of a second and 0.510 away from beating rainbow road. >_<.
WILL SOMEONE POST IN HERE GOD DAMMIT
I've only beaten a couple one on rainbow road, and another on mario circuit 1.
I beat tick tock clock by 2.678 seconds.

thats good, i beat tick tock clock well, but cant remember the time and my DS is charging now.
Well i've beaten 14:
Figure 8
Luigi's mansion
Tick tock clock
Mario circuit (Star cup one)
Airship Fortress
Wario stadium
Peach gardens
Bowser castle (Spec. cup)
Mario circuit (snes)
Luigi circuit (GC)
Baby Park
Koopa beach 2
Mushroom Bridge
Sky Garden.
I finished beating them all recently. My foster brother is
NOT pleased with me setting so many records he'll never beat.

He sucks so royally at that game, I've beaten a few of his times by over 10 seconds, and he worked so hard to set those

.
Times I'm semi-proud of. I know there's better ones, but I still like how good I did for my ability:
Figure-8-Circuit: Was: 1:27:005 Now: 1:22:532 (Staff Ghost: 1:34:481)
N64 Choco Mountain: 2:08:893 (Staff Ghost: 2:15:571)
GCN Yoshi Circuit: 1:45:391 (Staff Ghost: 1:48:793)
Peach Gardens: 1:48:970 (Staff Ghost: 1:52:989)
Mario Circuit: 1:49:802 (Staff Ghost: 1:56:533)
Those are some of my records I like a bit more than others. I know there's better out there, but I still like them nontheless... heck there's probably a few psychos out there that can easily finish Choco Mountain in under 2 minutes
EDIT: Played Figure-8-Circuit until my finger started to cramp from mini-turbos

But I set a nice record.
this is the one im most proud of: peach gardens, 1:52:986. staff record, 1:52:989. bring it!
lol that's funny, the only staff ghosts i have came colse to is yohsi falls by about .8 of a second, not bad considering i do not own a copy lol.
beaten every staff ghost except raindow road and donut plains
dnd, i found yoshi island quite hard, grats. what car did you use?